BAA 2022 February
Vol. 132 No. 1

Journal of the
British Astronomical Association

to Spaghetti
C/2021 A1 Nebula
Detecting exoplanets with the BAA
Journal of the 2022 February Vol. 132 No. 1
British Astronomical
Editor: Mr Philip Jennings Refereed papers
Papers Secretary: Prof Jeremy Shears Multiwavelength observation of polar faculae
Meetings Recorder: Alan Dowdell C. Alexandra Hart, Matt Penn & Peter Meadows 23
Jupiter in 1949 & the Revival of the South Equatorial Belt
Richard McKim 31
The Journal is published six times per year, in February,
April, June, August, October & December. R CrA & cyclic brightness variations in NGC 6729
Library subscription (UK and surface mail overseas): £76.00. Terry Evans & Grant Privett 49
To purchase single copies of specific issues please see
Notes & News
The Association is not responsible for individual opinions
expressed in articles, letters, reviews or reports of any kind. Photograph: C/2021 A1 (Leonard) Michael Jäger 3
Material published in the Journal does not necessarily From the President David Arditti 3
express the views of the BAA Trustees or Council. BAA instruments for sale Richard McKim 4
Nominations for the Ballot for the BAA Council & Board of Trustees Bill Tarver 4
Contributions In brief Philip Jennings 5
Papers should be sent by e-mail (preferred) or by post
(three copies) to the Papers Secretary at the address Auroral & NLC activity 2021 October 16 – December 15 Sandra Brantingham 5
shown inside the back cover of each issue. They will Imaging the James Webb Space Telescope on its way to L2 Nick James 6
be refereed, and, if approved by Council, published as Awards at the 2021 Christmas Meeting David Arditti 7
soon as reasonably possible. Those wishing to speak at a
meeting should contact the Meetings Secretary. Amateur observers contribute to research on white dwarfs in Jeremy Shears 8
cataclysmic variables
All other contributions should be sent to the Editor,
at As well as Letters to the Large-amplitude optical transient in Aries identified as a WZ Jeremy Shears 9
Editor, he will be pleased to receive contributions to Sagittae system
Observers’ Forum, particularly interesting astronomical Quiz answers Marie-Louise Archer et al. 10
images, drawings and photographs. Colour images are
especially welcomed. Photos and media will be returned Double star unexpectedly detected during occultation by Phil Denyer et al. 17
only if a suitable stamped addressed envelope is enclosed. asteroid – a first from the UK
Solar Section Lyn Smith 18
Advertisements Equatorial platforms, Part I Martin Lewis 21
Small advertisements should be sent to the Office, From the Journal archive John Chuter 22
accompanied by the appropriate remittance. Members’
small advertisements are FREE and may be sent directly Index to volume 131 Hazel McGee facing 34
to the Editor by e-mail.
Display advertisements and loose inserts: For a The Archives
rate card and further information, please contact the From the BAA Archives John Chuter 55
Journal Advertising Manager, Ms Marie-Louise Archer,
at: Review
Deadlines Rosetta: The remarkable story of Europe’s comet explorer (Bond) Nick James 57
Please send material for possible publication to the Editor
by the following dates:
Astronomy in a cold climate John Cook 57
Issue Date
2022 April
2022 June
2021 Feb 22
2022 Apr 25 BAA Update
Later dates apply, by arrangement, to electronic advertising copy Marlborough & Exmoor: Starlight & night light Bob Mizon 58
for which space has been reserved. Obituary: Dr Fiona Vincent (1949–2021) Roger Stapleton 59
Membership of the BAA Observers’ Forum
The annual subscription for Ordinary standard member- The Variable Star Section CCD target list Roger Pickard 60
ship of the Association for the 2021–2022 session is
£50.50. For details of concessionary rates, digital-only
The Little Lion – Leo Minor Callum Potter 61
membership and other information, see page 30 of this
issue. Members who pay UK income tax are requested Meetings Alan Dowdell
to complete a Gift Aid certificate in order to benefit the BAA Summer Meeting, 2021 June 26 62
Association, which is a registered educational charity. [To BAA Autumn Meeting, 2021 September 4 63
claim Gift Aid you must pay an amount of UK income
tax and/or Capital Gains tax at least equal to the tax
which we reclaim on your donations in the relevant tax
year (currently 25p for each £1 you give us).] Membership information 30
Errata in 2022 Handbook 59
Sky notes for 2022 February & March Nick Hewitt 64
Published by:
The British Astronomical Association, Meetings diary, notices & small advertisements 65
Burlington House, Piccadilly, London W1J 0DU Board of Trustees and Council, Session 2021–2022 67
Tel: 020-7734 4145
On the cover
The Spaghetti Nebula, SH2-240 Callum Scott Wingrove
Journal © British Astronomical Association 2022. Indi-
vidual articles, illustrations etc. remain the copyright of This supernova remnant in Taurus is large (about three degrees in diameter) but
the author or imager, whose permission must also be faint, so teasing out its structure required Callum to obtain a total of 42 × 300s
obtained before reproduction.
of exposure. This beautiful image was taken from Stanmore, Greater London
ISSN 0007–0297 on 2021 Dec 10, using an ASI 294MC Pro camera with a Samyang 135mm
The Magazine Printing Co., Hoddesdon, EN11 0FJ lens and STC Astro Duo-Narrowband filter.

2 J. Br. Astron. Assoc. 132, 1, 2022
Notes & News

C/2021 A1 (Leonard). The rapidly evolving tail of

From the President
this comet delighted observers through December,
as it fitfully brightened on its way to a 2022 Jan 3
perihelion. A full report on the comet will appear in
David Arditti due course. This 3.5°-wide field was captured by
Michael Jäger, Austria on 2021 Dec 28, at 19:20 UT.
He used an 8-inch Veloce telescope and QHY600,
T he President is, constitu-
tionally, the member who
presides at all BAA meetings,
Owing to COVID-19 interrupting normal ser-
vice for such a long time, I had four of these to
present at the Christmas Meeting: Steavenson
with a total exposure time of 10 minutes. – Ed.

including those for members, Memorial Awards to Alexandra Hart and Dale
Council and the Board of Trust- Holt, and Sir Patrick Moore Prize certificates to Telescopes in space & on Earth
ees. It is, as I remarked at the Mary McIntyre and Howard Parkin. (More de-
Christmas Meeting on 2021 tails are on p.7.) As I write this over the Christmas period, we
Dec 4, worth thinking about the meaning of the Descriptions of the BAA awards, with listings have just seen the successful (and long-awaited)
term and its origins. Why does the BAA have of all the recipients from 1930 to the present, can launch of the James Webb Space Telescope – a
a President? be found on our website under ‘About us’. The triumph both for NASA and ESA, and an enter-
Long before the term ‘President’ was used regular call will go out in the April Journal for prise that, should it succeed, is sure to intensify
for the head of any state, the word was chosen the next round of citations for the Walter Goo- popular interest in astronomy. I regularly see
by our national academy of science, the Royal dacre, Merlin, Lydia Brown and Horace Dall amazing results from amateurs who have ana-
Society (founded in 1660), as the name for the Medals, as well as the Steavenson Award. Do lysed and processed Hubble imagery, and I am
elected official tasked with ensuring order and have a look at the details on the website and start sure JWST will, if all goes well in the long term,
clarity of discussion in the meetings. These thinking now about whether you would like to provide another rich seam for amateur exploita-
meetings were conceived as essentially demo- nominate anyone this year. Any queries on these tion and pro-am collaboration: grist to the mill
cratic, decisions on the operation of the society should be directed to the Business Secretary, for those of our members who like to work on
being taken by votes of all fellows (members) Bill Tarver (see p.67 for contact details). professionally acquired data.
present. The President was therefore never (in We also distribute funds to our members I cannot see any prospect of the BAA putting
modern terms) an ‘executive’; he was a facili- through the Ridley Grant scheme. This enables a telescope into space for our members in the
tator of a collegiate decision-making process. members to purchase equipment for their ob- near future, but we are hoping soon to provide
Words with similar meanings to this original us- serving projects. We recently decided to ex- them with observing time on remote telescopes
age are ‘chair’ or ‘convenor’. tend this to also support travel to conferences in good observing locations, equipped with the
When the Royal Astronomical Society was (though of course there have been none to go to latest cameras, as a membership benefit at no
formed in 1820 (as the London Astronomical of late). Again, contact the Business Secretary extra cost. Watch this space.
Society, and effectively an astronomical break- for more information.
away group from the Royal Society), it adopted We spend funds not only on our members,
similar governing principles, and chose its own but on the wider popularisation of astronomy. A
President with the same function. Then, when new venture in 2021 December was our spon-
the BAA was formed in 1890 (arguably as a sorship of an external web forum: SolarChat!
kind of break-away group from the RAS, focus- ( A number of BAA
ing more on the needs of the amateur observer), members are already involved with this site,
that process was repeated, with a similar gov- which has a reputation for being a friendly and
erning structure adopted. That is why the BAA welcoming place for beginners and experts
has a President, who is not merely a figurehead alike. This sponsorship should increase our
but who works in an honorary capacity for the prominence amongst amateurs internationally,
Association on a day-to-day basis, chairs all its and hopefully attract some more to join.
meetings, and is involved with all significant
decisions. The term goes back a long way and
we use it in its original sense, which should be Legacies
understood without the executive implications
that came about after the United States of Amer- We can do these things because our finances
ica, and then many other nations, decided they are strong, and an important component is the
would be led by someone with that title. money that we are left in legacies by members
and well-wishers. I wish to take this opportu-
nity to thank the estate of late member Mr Paul
Awards, grants & sponsorship Fulford for a recent donation of £9,000, this be- An Ariane 5 rocket launches the James Webb Space
ing the first part of a bequest to the Association. Telescope on 2021 Dec 25. Some members suc-
One of the nicest duties for the President is pre- Please do consider leaving the BAA something ceeded in imaging the telescope in the days that
senting the awards and prizes of the Association. in your will. followed (see p.6). (NASA/Bill Ingalls)

J. Br. Astron. Assoc. 132, 1, 2022 3
Notes & News

BAA instruments for sale Notice

T he following instruments are for sale by
sealed bid. Four previous auctions have
been held, and all items advertised have been
components show some signs of wear consistent
with age:
condition. A suitable power transformer
will be included and will not be subject to
return. Guide price: £20. An optics tube
sold (see the 2021 October Journal, 131(5), 268 356 A 3×3-inch format lens. 12-inch focal with the 10cm aperture objective used by
(2021)). length, ƒ/7.7, by Dallmeyer. Donated by Mr Hendrie for his photographic work with
W. W. Mellor in 1991. Guide price: £75. the filter could be made available by sepa-
rate arrangement.
Item number & description 357 Ross wide-angle Xpres camera lens, 52mm
diameter and 5-inch focus. Donated by Photos of these items are available from the un-
The first item may be familiar to visitors to the W. W. Mellor in 1991. Guide price: £75. dersigned (,
old BAA library: who will answer any questions prospective pur-
384 Large-format Pentac lens, 64mm diameter chasers may have. The instruments are currently
86 Donated by C. Waller in 1943. A Smith’s and 14-inch focal length, ƒ/5.6. Donated by stored in Northamptonshire.
12-inch (30cm) diameter celestial table globe T. W. Rackham in 1992. Guide price: £180. The prices given are for guidance only and
(English, mid-19th century) on a wooden are not formal valuations. The highest bid ex-
altazimuth stand. The manufacturer has 386 Metal cell containing a mounted 70mm di- ceeding the guide price will be the winner.
added the following text: ‘Containing all the ameter lens. This is an 8-inch focus ƒ/2.9 On this occasion, with the single exception of
known Stars, Nebulae &c. Compiled from Pentac lens. Donated by T. W. Rackham in the globe, bids below the guide price will also
the Works of WOLLASTON, FLAMSTED, 1992. Guide price: £150. be considered.
DE LA CAILLE, HEVELIUS, MAYER, If you wish to bid, you can do so only through
BRADLEY, HERSCHEL, MASKELYNE. 401 Ross 21-inch focus homocentric ƒ/8 pho- the post by sending an envelope with your bid
The Transactions of the ASTRONOMICAL tographic lens, diameter 67mm, in a box. to Dr R. J. McKim at the address of the Director
SOCIETY OF LONDON.’ Published by Donated by H. B. Ridley in 1994. Guide of the Mars Section, printed on the inside rear
Smith & Son, 63 Charing Cross, London. The price: £160. cover of the Journal. State your bid, full name,
stand is cracked in a few places but could be postal and e-mail addresses, telephone number
repaired. The globe itself is in good condition, The final item is a hydrogen-alpha solar filter and BAA membership number if you know it.
though the glazing has become crazed. It was (bandpass 6562.8 ångströms) by Daystar: The auction is not open to non-members, but
for many years kept on the top of bookcases the Association reserves the right to make ar-
at the BAA library, and was never placed on 363 A Daystar filter was donated by rangements for any remaining instruments to
loan. Smith & Son apparently moved to their W. W. Mellor in 1981 and never placed be sold in whatever manner it may choose. The
Charing Cross premises in 1870. The firm upon loan. It is probably no longer in work- envelope must be posted to arrive at the latest on
was taken over later by George Philip & Son. ing order, but we offer instead an identi- Mar 1. All bidders will be contacted by Mar 15,
Examples have been sold for over £1,000 cal item in much better condition, which and all instruments should be paid for by Apr 30
by Bonhams and Christie’s. We have seen came from the estate of the late Michael (after which they may be re-advertised).
such items described as ‘circa 1864’. Guide Hendrie. Mr Hendrie was still using this No money should be sent with your bid. Pay-
price: £500. device a decade ago (Journal, 122, 97–104 ment and collection will be arranged with the
(2012); ‘Farewell to film: Imaging comets successful bidder. In each case you will be re-
The following items are all lenses, being and the Sun the old way’). We recognise sponsible for collecting the item from
among items seized by the police from Mr R. A. that such filters deteriorate with time, and Northamptonshire. If you are unsatisfied with
Marriott’s home in 2019, and awarded to us this one has not been recently tested. There- your purchase, you may return it within a month
through our action in the Northampton County fore, we are offering it with a very low re- for a full refund.
Court last year [131(5), 267 (2021)]. The optics serve price, and we will refund the money
appear to be in good condition, though metal at once if it is found not to be in working Dr Richard McKim, for the BAA Trustees

Nominations for the Ballot for the BAA Council & Board of Trustees

A n election will be held in 2022 October for the Council of the Asso-
ciation and the Board of Trustees. A ballot list will be sent to mem-
bers with the August Journal.
you must be a paid-up member. Please ask two other paid-up members to
propose and second you and then sign the letter or form yourself to show
you are willing to stand. If you wish to nominate someone else, the same
Under the constitution approved in 2015 May, the elected Council conditions apply. If standing as a Trustee, you must confirm that you have
comprises the President, Treasurer, three Secretaries, and up to five read and understood the responsibilities of the Trustees of a Charity as set
further members of the Association. Additionally, all Section Directors, out on the website of the Charities Commission and that you are prepared
Postholders, the elected Board members and the Vice-President (ex to accept and fulfil these responsibilities to the best of your ability.
officio) are automatically members of the Council. All nominations must be in writing and sent to the BAA office to arrive
The Board of Trustees comprises the President, Vice-President, by Sunday, 2022 May 8. A suitable form (if wanted) may be downloaded
Business Secretary, Treasurer and five elected members, all of whom from the BAA website at: Signed and
will also be Council members. You can stand for election to Council scanned forms or letters may be returned to the office by e-mail [office@
without being considered for the Board, but you cannot be elected to the] or by post.
Board without also becoming a member of Council.
If you would like to be nominated as a Trustee or a member of Council, Bill Tarver, Business Secretary

4 J. Br. Astron. Assoc. 132, 1, 2022
Notes & News

In brief formed by supernovae in the last 10–20 million
years; by chance the Sun is travelling through
the region and is roughly at its centre.
Sherwood Observatory success
Sherwood Observatory, the home of the Man-
Published in Nature in 2022 January, a pa- sfield & Sutton Astronomical Society, has
Local stars are Bubble-born per by Catherine Zucker et al. (go.nature. secured £2 million of funding for a planetari-
com/346Yqak) finds that all local star-forming um and Science Discovery Centre. A further
The formation of all nearby young stars is driv- regions lie on the Bubble’s surface, where mo- £3 million is needed for the project, but if all
en by expansion of the Local Bubble which sur- lecular clouds have collected from the gas and goes well, the centre may open in 2024.
rounds the solar system, a new paper finds. dust swept up by its expansion.
The Bubble, about 1,000 light-years in diam-
eter, is a non-spherical cavity of plasma at about
one-tenth of the average density outside it, sur-
Astronomy Photographer of the Ken Medway (1951–2021)
rounded by a dusty shell. It Year 2022 As this Journal went to press, sad news emerged
is believed to have been that Ken Medway, a much-respected solar ob-
The annual astrophotography competition, now server and past Director of the Solar Section,
▶ Some star formation oc- in its 14th year, is open for entries until 2022 has died. An obituary will appear in due course.
curs within the naked-eye Mar 4. Submissions are encouraged from pho- Many condolences to all who knew Mr Medway,
Pipe Nebula in Ophiuchus, tographers of all skill levels. Winners will be who will be much missed.
situated at the surface of announced at an online awards ceremony in the
the Bubble. (Image: Nick Hewitt) autumn. See for details. Philip Jennings, Editor

happened last year). An approximate gauge for
Aurora & Noctilucent Cloud Section cloud onset is when the mean zonal wind at
60°S latitude and 10hPa (~30km altitude) shifts
Auroral & noctilucent cloud activity 2021 from westerly (winter) to easterly (summer).
This is because that shift marks (approximately)
October 16 – December 15 when the circulation in the middle atmosphere
first acquires enough summertime characteris-
tics – in particular, ascending and thus cooling
Sandra Brantingham storms, one S1-class storm and 11 sightings. air in the polar mesosphere – to be conducive
Director The first 10 were on Nov 3/4 by Lyn Smith from to noctilucent cloud formation.’ According to
Brechin, Denis Buczynski from Tarbatness, NASA’s Ozone Watch website, the switch from

W ith coronal mass ejec-
tions and sunspot num-
bers regularly in double or
Lynne Cattanach from Arbroath, Mark Phillips
from West Edinburgh, Mary McIntyre from
Tackley, Oxford; Ronan Newman from Conne-
westerly to easterly happened on Dec 13, and
CIPS saw the first clouds on Dec 14.

even triple figures, and several coronal holes mara, Galway; Tracey Harty from Penrhyn Bay,
being recorded, the Sun is now lifting out of North Wales; Bill Samson from Dundee, James General
minimum and at a faster rate than forecast. Au- Hilder from Gatehouse of Fleet, South Scotland
rora sightings over this period are at 21, while and Jay Brausch from North Dakota. The final There is a website for those of you who are
noctilucent cloud (NLC) sightings are at zero. sighting was on Nov 4/5 by Lynne Cattanach stuck in light-polluted areas or out of range of
from Arbroath. the aurora. It is a webcam ( op-
In early December, there was one R1-class erated by the Shetland tourist board, that looks
Aurora storm and there were no sightings. north and, if there is no cloud, will give a good
view of any aurora or NLC (and you can lis-
In late October there was one G1-class storm, ten to the waves and sea birds). In addition to
three S1-class storms, one R3-class storm and Noctilucent cloud this, they have added two more cameras further
three R1-class storms, with 10 sightings. The north specifically for the aurora. These are at
first was on Oct 18/19 by Alan Tough, from Noctilucent cloud has been very late in starting
Elgin. The next nine took place on Oct 30/31 in the southern hemisphere for 2021/’22, even I would like to thank all the observers who
and were by myself from Glenbarry, Bill Ward later than for 2020/’21, with the first detection have contributed, and I ask you to keep sending
from Dingwall, Gordon Mackie from Thur- via the AIM satellite on 2021 Dec 14. As I write in those reports to
so Bay, Alan Tough from Hopeman, Moray; this on Dec 18, it has only extended down to
Len Entwisle from Elland, West Yorkshire; 75°S and comprises just three small patches.
Tracy Harty from Great Orme, North Wales; Prof Cora Randall, principal investigator for Below: the display of Nov 3/4, observed by (from
Jim Henderson from Deeside, Aberdeenshire; the AIM Cloud Imaging & Particle Size (CIPS) left to right): Lynne Cattanach from Arbroath,
Frances Goodman from Aberlady Bay, East Lo- instrument, said: ‘We expected a late start to Tracey Harty from Penrhyn Bay, North Wales and
thian and Denis Buczynski from Tarbatness. the [southern-hemisphere] season this year be- Denis Buczynski from Tarbatness.
In November there were two G3-class cause winter-like conditions persisted in the
storms, one G1-class storm, three R1-class stratosphere longer than usual (similar to what

J. Br. Astron. Assoc. 132, 1, 2022 5
Notes & News

Imaging the James Webb
Space Telescope on its way
to L2
Nick James performed perfectly until shutdown and sepa- Above: JWST at 1,000km above the Earth, follow-
Director, Comet Section ration at T+ 8m 47s. After separation, JWST ing separation. ESA/CNES/Arianespace
was propelled by the five-metre-long Ariane

F inally, at 12:20 UTC ESC-A upper stage for a further 16 minutes.
on Christmas Day, the This placed it on the required transfer trajectory
James Webb Space Tele- towards its final destination: a halo orbit around
scope (JWST) left the the L2 Lagrange point, 1.5 million kilometres
Earth atop an Ariane 5 ECA launch vehicle. from Earth.
Thirty seconds after launch it disappeared into The JWST Optical Telescope Element (OTE)
thick clouds above the French Guiana launch is a 6.5m, ƒ/20, Korsch three-mirror anastigmat.
site, but the Ariane core stage and solid boosters This consists of an ellipsoidal primary, made
up of 18 hexagonal, gold-plated, First submitted image, taken by
beryllium segments, a 0.74m hy- Denis Buczynski on 2021 Dec 25
Launch, on 2021 Dec 25. ESA/ perbolic secondary and a small at 21:56 UTC. 0.36m SCT, ƒ/6,
CNES/Arianespace ellipsoidal tertiary. The telescope ASI 1600MM, 25×3s. Range:
and its instruments are designed 110,000km.
to operate at red to infrared wave-
lengths (λ = 0.6 to 28 microme-
tres). Since it is observing in the
infrared, the telescope must be
cold. To ensure a long mission
lifetime, it is passively cooled by
a 21×14m, five-layer, aluminium-
coated Kapton sunshield.
All the complex elements of
the observatory had to be folded
up to fit within the Ariane fair- JWST (left) after sunshield deployment, and
ing; they would then be deployed the upper stage (right). Taken by Nick James on
2021 Dec 31 at 22:00 UTC. 0.28m SCT, ƒ/10, ASI
during the journey to L2. The
6200MM, 5×60s. Range: 680,000km.
first critical deployment was the
solar array and the Ariane injec-
tion attitude was so good that this
occurred earlier than expected, with the sunshield fully deployed but not yet
while the spacecraft was still vis- tensioned, JWST was magnitude 14.5 at a range
ible in the upper-stage forward- of 800,000km. This implies that it will be around
camera video feed. At the time of magnitude 16 at L2 (although this will strongly
writing (2022 Jan 3), all the other depend on the solar aspect angle). That should
deployments, including that of the make it a relatively easy imaging target.
sunshield, have gone well. The upper stage performed a final burn after
We have been able to image telescope separation, to ensure that it would not
JWST as it moves away from collide with the spacecraft. While JWST itself is
Earth, since it was conveniently precisely tracked by radio, the upper stage is
situated in Orion. The first image passive and so astrometry is useful to determine
submitted was obtained by Denis where it will end up. As of 2022 Jan 2, the upper
Buczynski, at 21:56 UTC on the stage was magnitude 17.4 at a range of
night of the launch. At that time 890,000km. I have used astrometry from Peter
the spacecraft had a high appar- Carson, Denis Buczynski, Patrick Wiggins and
ent motion and so it appears in myself to determine its future trajectory with
the photograph as a streak mov- Bill Gray’s FindOrb program. It will enter a he-
ing relative to the background liocentric orbit, with a period of just over 380
stars. Later images were submit- days, and will fade below magnitude 20 in early
ted by Peter Carson, David Swan, 2022 February. The stage will return to Earth’s
George Carey, Dave Eagle, Tim vicinity in the summer of 2047, reaching magni-
Haymes and me. On 2022 Jan 2, tude 20 for a short time.

6 J. Br. Astron. Assoc. 132, 1, 2022
Notes & News

Mary McIntyre with the Sir Patrick Moore
Prize certificate presented to her at the The 2021
meeting. (Photo courtesy Mary McIntyre)

Mary McIntyre gives around 50 lec-

tures per year on astronomy and astro-
photography; she specialises in the his-
tory of women in astronomy, and other
subjects. She speaks to adult groups like
the University of the Third Age (U3A)
and the Women’s Institute, as well as Lyn Smith
to schools and youth groups like the Walter
Cubs and Scouts, in addition to giving Goodacre
audio-only talks to visually impaired
Medal & Gift
Awards at
groups. She has a YouTube channel
where she presents tutorial-style videos teach-
ing techniques of observation and imaging. She

the 2021 has regularly been on the radio and has pro-
duced podcasts. In addition, she writes for BBC
Sky at Night magazine and oversees the UK Dale Holt
Christmas Women in Astronomy Network (UKWIAN)
social media pages. She even runs outreach
events in her back garden. She does all these

Meeting in spite of mobility issues. We consider her an
outstanding ambassador for astronomy.
Howard Parkin is a leading light in astron-
omy on the Isle of Man (from which he had
David Arditti journeyed to attend the meeting). He was a
President founder of the IoM Astronomical Society, and Fitz-Gerald
since 1985 he has been giving adult education
Merlin Medal
A t this meeting, I presented
both the 2020 and 2021
Steavenson Awards, as well as
classes on the island. He has talked to ministers
in the Isle of Man government, and was instru-
mental in getting Dark Sky Discovery Site sta-
& Gift

certificates to two winners of the tus for 26 areas. He also advised the Isle’s
2021 Sir Patrick Moore Prize. postal authority on producing astronomy-
The Steavenson Award consists of books themed stamps. He regularly visits schools and Raffaello
and is given to a member who has made an hosts groups of Scouts and Guides at the Isle of
outstanding contribution to observational as- Man Observatory, helping them to get their as- Lena
tronomy. It was won in 2020 by Alexandra tronomy badges. He also has a regular pro- Merlin Medal
Hart (as detailed in the 2021 February Jour- gramme on Manx Radio. Howard has brought
& Gift
nal). She was present to accept her award: the many people to the subject through an enthusi-
book Solar Astronomy. asm for astronomy that crosses all age groups
The Steavenson Award was won in 2021 and abilities.
by Dale Holt. Dale was cited as a prolific ob-
server of the deep sky, having submitted 760 David Arditti, President Howard
observations to the Deep Sky Section between
The other 2021 awards (see panel at right) will be
2007 and 2021. He has developed a unique
method of observation, using a video camera more fully detailed in the Journal when they are for- Sir Patrick
mally presented. Congratulations to all.
at the focus of his 505mm telescope, then feed- Moore Prize
ing the signal to a monitor and making pencil
sketches of the image that are scanned, thus
combining old and new technology. He often
records under-observed objects, such as gal-
axies in the ARP and Hickson catalogues. His Mary
sketches regularly appear in the Journal and McIntyre
the Deep Sky Section Newsletter, and have
featured in Sky & Telescope magazine. Dale Sir Patrick
received a book token from the President. Moore Prize
The Sir Patrick Moore Prize was won joint-
ly this year by three people who have excelled
in encouraging public interest in astronomy:
Mary McIntyre, Howard Parkin, and Andrew
Robertson. The Prize to each of them was
£250, plus a year’s free membership of the As-
sociation and a certificate. Mary and Howard
The President hands Alexandra Hart her 2020 Andrew
Steavenson Award, at the 2021 Christmas Meet-
were able to attend the meeting. (Andrew is ing. Photographs of the presentations to the 2021 Robertson
intending to have his presentation at the Not- winners will appear in the full report of this
tingham meeting in June.) meeting. (Photograph by Marie-Louise Archer) Sir Patrick
Moore Prize

J. Br. Astron. Assoc. 132, 1, 2022 7
Notes & News

Variable Star Section

Amateur observers contribute to research on
white dwarfs in cataclysmic variables
Jeremy Shears This work doubles the
number of CV white
C ataclysmic variables (CVs)
are compact interacting bi-
naries in which a white dwarf
dwarfs with an accurate
mass measurement
is accreting material from a low-mass donor,
generally a late main-sequence star. The study
of CVs has long been a fruitful area of coopera-
tion between amateur and professional astrono- Notices, also included several Vari-
mers. Long-term light curves by amateurs have able Star Section observers.
underpinned models of CV physics. Amateurs
have also been involved in the discovery and
characterisation of new CVs, especially in the Pro-am opportunities
present time when many new systems are be-
ing revealed by large synoptic surveys, such So why is the field of CV research
as Gaia and Pan-STARRS. It is common for so fruitful for pro-am collabora-
amateurs and professionals to collaborate in this tion? Well, while amateurs might
research and to jointly publish the results in the
Drawing of a cataclysmic variable, showing a white dwarf have relatively small telescopes,
scientific literature. accreting material from a red dwarf. (Dr Helena Uthas) they do have the advantage of ac-
A paper published in 2021 November in cess to them whenever they choose
Monthly Notices of the Royal Astronomical (weather permitting!). Moreover,
Society, on ‘Constraining the evolution of cata-
These systems are relatively bright and numer- because amateurs are located around the world
clysmic variables via the masses and accretion ous in our galaxy; they thus represent the best at different longitudes, they can obtain near-
rates of their underlying white dwarfs’,1 is a laboratory to constrain the key ingredients of continuous photometry. By contrast, profes-
great example of this collaboration. The prin- the models describing the evolution of all types sionals tend to have limited time on much larger
cipal author is Dr Anna Pala, currently a Eu- of compact binaries. One reason why this is im- telescopes, which is usually scheduled well in
ropean Space Agency Research Fellow, who portant is that some types of CV are understood advance. However, they are able to obtain more
conducted the work whilst at the European to be precursors of Type 1a supernovae. A Type detailed astrophysical data and this is often sup-
Southern Observatory in Garching, Germany. 1a supernova explosion occurs when the white plemented with multiwavelength observations
dwarf grows to near the Chandrasekhar limit of from satellites.
The author list includes researchers at universi-
approximately 1.4 times the mass of the Sun.
ties around the world, and several Variable Star Therefore, the activities of professionals
Section observers. The Monthly Notices paper presents the mass- and amateurs are complementary: working to-
es, temperatures, and accretion rates of 43 CV gether across our community, both in obtain-
white dwarfs. Dr Pala combined analysis of ultra- ing the data and analysing it, has been common
The paper violet data from the Hubble Space Telescope with practice for many years. There exists a mutual
parallaxes provided by Gaia Data Release 3. This trust and desire for understanding these sys-
Dr Pala’s research focuses on understanding work doubles the number of CV white dwarfs tems that I believe is the key to the success of
how the component stars in a CV system evolve. with an accurate mass measurement. this collaboration.
The mean mass is 0.81 If you wish to become involved in observing
solar masses (range 0.61 cataclysmic variables, either visually or elec-
to 0.97), but the distribu- tronically, please contact the Section Director
tion shows a tail extend- (see p.67 for details).
ing towards low masses,
with some below 0.5 solar
masses. Such low masses References
are consistent with either
helium-core or, possibly, 1 Pala A. F., Gänsicke B. T., Belloni D., Parsons
hybrid CO/He-core white S. G., Marsh T. R., Schreiber M. R., Breedt E.,
dwarfs. There was no evi- Knigge C., Sion E. M., Szkody P., Townsley D.,
Bildsten L., Boyd D., Cook M. J., De Martino D.,
dence for a clear relation- Godon P., Kafka S., Kouprianov V., Long K. S.,
ship between the mass and Monard B., Myers G., Nelson P., Nogami D.,
the orbital period. Oksanen A., Pickard R., Poyner G., Reichart D. E.,
An earlier paper by Dr Rodriguez Perez D., Shears J., Stubbings R. &
Pala on ‘Effective tempera- Toloza O., Mon. Not. R. Astron. Soc. [https://doi.
tures of cataclysmic-vari- org/10.1093/mnras/stab3449] (2021). Also
able white dwarfs as a probe available at
Dr Anna Pala, European Space Agency Research Fellow (the VLT of their evolution’,2 like- 2 Pala A. F., Gänsicke B. T. & Townsley D. et al.,
complex is just visible in the background). wise published in Monthly Mon. Not. R. Astron. Soc., 466, 2855–2878 (2017)

8 J. Br. Astron. Assoc. 132, 1, 2022
Notes & News

Variable Star Section

Large-amplitude optical transient in Aries
identified as a WZ Sagittae system
A n optical transient was reported by the
MASTER survey at magnitude 15.1 on
Nov 26.826. It was also independently dis-
covered by Japanese amateur astronomer
Yuji Nakamura, at 11.7mag (unfiltered) on
Nov 28.469, using a 10cm ƒ/3.0 refractor and
CMOS camera.
The progenitor appears to have been mag-
nitude 21.9r, suggesting an amplitude of ~10
magnitudes. The large amplitude and early
spectroscopy suggested that it might be a nova:
possibly a young helium nova. This would have
been especially exciting as it is rare to find a
nova in Aries. However, as further spectros-
copy and photometry became available, it was
actually identified as a dwarf nova of the WZ
Sge type.
WZ Sge stars are a subclass of the SU UMa
family, but they are more highly evolved sys-
tems. They have very short orbital periods, long
intervals between outbursts (typically decades)
and exceptionally large outburst amplitudes,
usually exceeding six magnitudes.
Whilst it might have been nice to have cel- Light curve of the transient in Aries. Data: BAA VSS, AAVSO, VSOLJ (vis., V, CV) and ASAS-SN (g).
ebrated Nova Arietis 2021, the episode never- Note that the ‘v’ symbols (in red) are limit values which indicate negative (‘fainter than’) observations
by ASAS-SN before the transient was detected.
theless provided a fascinating insight into as-
tronomical research in real time. As new data
became available in the first few days follow-
ing discovery, new insights were gained and
ideas about the nature of the transient had to
be modified. The orbital period was found to be
0.05935d (85.46min) and with an outburst am-
plitude of 10 magnitudes, it might well be the
largest-amplitude WZ Sge system on record.
A light curve of the transient accompanies
this article, along with a fine image of the field
taken by Mazin Younis from a dark site in
southern Morocco, where he was visiting when
the transient occurred. At the time of writing, it
is still above quiescent magnitude. This situa-
tion might exist for several weeks or months
until it finally returns to its slumbers, before
returning to the stage some time, likely de-
cades, in the future. Image of the transient in Aries, MASTER OT J030227.28+191754.5, on 2021 Nov 29. Field size 0° 59ʹ
× 0° 41ʹ. Equipment: Sky-Watcher Esprit 100ED refractor and ZWO ASI 294MC-Pro. Exposure: 12
Jeremy Shears, Director minutes. (Mazin Younis)

Eclipsing Binary Observing Guide
Hard copies of the revised Variable Star Section Eclipsing Binary Observing Guide by Des Loughney
can be purchased from the BAA online shop:
The standard price is £7.50, or £6.00 for members. Many thanks to Ann Davies for arranging the printing of this valuable
book. We will have copies available on the BAA Sales stand at future events. It can also be downloaded free of charge

J. Br. Astron. Assoc. 132, 1, 2022 9
Notes & News

the model is Billy, one of the editor’s cats), ISAS, JAXA, Akatsuki; Processing by Meli thev (8), Ethan Tweedie Photography (28).
Image credits: David Davies (14), ESO (15), NASA (19, 34), NASA/JPL-Caltech (4), NASA/SDO (31), Sara the Freak on Unsplash (30), P. Jennings (22;
Q15 Q23 Q4 Q34 Q12 Q14


Q30 Q22 Q8 Q19 Q31 Q28

Quiz answers The answers to the Christmas Quiz (see 131(6), pp. 338–339 for questions in
full). Winners will be announced in the April Journal.

4. What title is given to the photo [see 2021
Prof Jeremy Shears, Director,Variable December Journal, p.338]? ‘The Pale Blue
Star Section: Dot’. What is its significance? It shows Earth
in a scattered ray of sunlight as just a point of
1. Which recurrent nova caused great ex- light, about the size of a pixel.
citement by erupting in 2021 and when was This iconic photograph was taken on 1990
its previous outburst? RS Ophiuchi was re- Feb 14 by NASA’s Voyager 1 probe at a dis-
ported in eruption on 2021 Aug 8. The nova tance of 3.7 billion miles from the Sun. As the
reached a peak visual magnitude of approxi- spacecraft was nearing the fringes of the solar
mately 4.5 the day after discovery. It has pre- system, mission managers commanded it to turn
viously been observed to erupt in 1898, 1933, its cameras for one last look at its home planet.
1958, 1967, 1985 and, most recently, in 2006 It snapped a series of 60 images that were used
February. A further two eruptions, in 1907 and to create the first ‘family portrait’ of our solar
1945, have been inferred from archival data. system, including the photo of Earth. The probe
RS Ophiuchi is a binary system consisting of a took the Pale Blue Dot photo just 34 minutes
white dwarf and a red-giant companion, with before its cameras were shut off forever.
an orbital period of around 454 days. The Voyager imaging team wanted to show
Earth’s vulnerability – to illustrate how fragile
2. Which word links (a)–(e) [See 2021 De- and irreplaceable it is.
cember Journal]? ‘Ganymede’. Ganymede Ganymede: one of the four Jovian moons discov- In his 1994 book Pale Blue Dot, Carl Sagan,
is the largest of the solar system’s moons and ered by Galileo. (NASA/JPL) who was a member of the Voyager imaging
one of the four Jovian moons first identified by team, commented: ‘It has been said that astron-
Galileo in 1610. The moon is situated between omy is a humbling and character-building expe-
Europa and Callisto. Its orbit around Jupiter has called JUICE (JUpiter ICy moons Explorer), to rience. There is perhaps no better demonstration
a period of about seven days. Possessing a me- be launched in 2022, which will reach Jupiter in of the folly of human conceits than this distant
tallic core, it is the only moon known to have its 2029 and enter Ganymede’s orbit in 2030/’31. image of our tiny world. To me, it underscores
own magnetic field (magnetosphere). Its surface Jeeves was the valet of Bertie Wooster in our responsibility to deal more kindly with one
is composed of half water ice and half silicate novels by P.G. Wodehouse (whose nickname another, and to preserve and cherish the pale
rock; of particular interest are the long, curved was ‘Plum’). The ‘Ganymede’ was the private blue dot, the only home we’ve ever known.’
grooves in its crust, which are unique (they are London club frequented by Jeeves and located
concentric to a point near Ganymede’s equator). in Curzon Street, Mayfair.
It is not known how they were formed; theories John Cook, Director, Radio Astronomy
range from a large ancient impact event to them Section:
being the result of tectonic activity due to tidal Nick James, Director, Comet Section:
heating. Ganymede, like Europa and other sat- 5. Who was the first person to spot the ra-
ellites, has a salty ocean underneath its crust, 3. Exactly when in 1959 did George Alcock dio signature of a pulsar? Jocelyn Bell, at the
which might harbour life. discover his first comet and in which con- Mullard Radio Astronomy Observatory, near
Several spacecraft have flown by Ganymede: stellation was it? Less than a week later, Cambridge, in 1967. It was her PhD super-
Pioneer 10 & 11 in 1973 and 1974, and Voyager he discovered his second comet, which he visor Antony Hewish who initially received
1 & 2, returned striking images during their fly- sketched. Where was that comet? The first credit for it.
bys. The Galileo probe discovered Ganymede’s comet (C/1959 Q1) was discovered on 1959 The Observatory was running a project to
internal ocean and magnetic field in the 1990s. Aug 25, 20:42–23:50 UT, in Corona Borea- observe the scintillation of radio signals in
Between 2019 and 2021, Juno performed two lis. The second was C/1959 Q2 and it was in the very-high-frequency spectrum. They had
flybys of Ganymede, providing images of the Cancer when he sketched it on the morning of filled a four-acre field with dipole aerials, all
moon’s polar regions. ESA plans a mission Aug 30. connected to a receiver and a pen recorder to

10 J. Br. Astron. Assoc. 132, 1, 2022
Notes & News

Left: William Herschel (1738–1822). Central: A full-sized replica in brass and rosewood of Herschel’s
Dame Jocelyn Bell Burnell. (With kind permission seven-foot reflecting telescope. Right: Herschel’s delightful garden: a site of great astronomical impor-
of Julia Hegecoe) tance. (Photographs by Marie-Louise Archer)

show changes over time. Jocelyn Bell (sub- 7. What connects a composer, a sister who Dr Paul Abel, Director, Mercury & Venus
sequently Jocelyn Bell Burnell) was a PhD discovered several comets, and the building Section:
student in 1967, analysing the output. She no- shown [see 2021 December Journal, p.338]?
ticed a signal repeating with a period of about The Herschel family. 8. What discovery in 2020 September
one second. Initially thought to be some form William Herschel is regarded today as ‘the prompted speculation that there could be
of man-made interference (radio pollution), it father of modern cosmology’. He grew up in alien life in our solar system? The discov-
soon became clear that this was probably not Germany and came to England at the age of 19 ery of phosphine in the atmosphere

Ben Mills
the case. She re-checked about three miles to work as a musician. His preoccupation as a of Venus.
of paper tape recordings, identifying some composer and musician dominated his life until Scientists at Cardiff Uni-
further repeating signals with different peri- his early 40s and he secured several positions, versity announced in 2020
ods. Careful analysis showed that they were including organist of the Octagon Chapel, Bath. that spectroscopic analysis
indeed from objects well outside the solar It was only in middle life that his interests ex- of data from the Atacama
system, later identified as fast-rotating neu- tended to astronomy. Large Millimetre/submil-
tron stars, which had been predicted by Baade He became a skilled telescope maker and in limetre Array (ALMA) in Chile and
and Zwicky in 1934. With a chance alignment 1781 discovered Uranus. He named it Geor- the James Clerk Maxwell Telescope in Hawaii
beaming their radio emission in our direction, gium Sidus, the Georgian Star, in honour of had detected phosphine in Venus’ atmosphere.
they were named pulsars. King George III, who then appointed him Court On Earth this colourless, toxic gas is a distinc-
Astronomer. Herschel also pioneered the use of tive biomarker and is often found in places
6. What aspect of a solar flare is responsible astronomical spectrophotometry and discovered that host anaerobic life, such as lakes. So, it
for sudden ionospheric disturbances, which infrared radiation. He is credited with the dis- seemed reasonable that phosphine detected on
we record at very low radio frequencies? covery of Titania and Oberon (moons of Ura- Venus might also indicate life.
The X-ray and ultraviolet (UV) radiation pro- nus) as well as Enceladus and Mimas (moons Numerous inorganic origins of the gas,
duced by the flare, which rapidly increases the of Saturn). He catalogued over 2,400 nebulae such as lightning and meteorites, were ruled
ionisation level in Earth’s ionosphere. and star clusters. He was honoured as the first out and it was concluded that bacteria, adapted
A solar flare is produced when the com- president of the Royal Astronomical Society in to the extreme conditions on Venus, could be a
plex, twisted magnetic field around an ac- 1820. These achievements were especially re- possible source. The discovery naturally made
tive region collapses and reconnects in a less markable given that he was self-taught. headline news around the world. However,
complex way. Huge amounts of energy can His sister Caroline’s scientific accomplish- over the last year there has been widespread
be stored in these magnetic fields, and the ments have sometimes been downplayed in debate as to the validity of this assumption.
sudden release of this energy creates radia- deference to her brother’s, but she also had a Two months after their original findings were
tion over a wide spectral range. Solar observ- remarkable career and was a significant astron- published, the team at Cardiff University cor-
ers can see the flare as a bright region in an omer in her own right – she discovered eight rected these results; reprocessed data from the
H-alpha telescope. The X-ray and UV energy comets and 14 nebulae. ALMA observations show amounts of phos-
in particular interacts with Earth’s ionosphere, The images above show William Herschel’s phine approximately one-seventh of the earlier
often creating problems with long-distance Bath residence, now the Herschel Museum. estimate (although they maintain they had de-
radio communications. The lowest part of the Several of his homemade telescopes are ex- tected the gas).
ionosphere, the D-region, is largely created hibited, and it has a delightful garden which Several studies have re-examined the origi-
by solar radiation, and a sudden increase in includes the site where his famous discovery of nal data and found no evidence of phosphine;
UV flux will increase its level of ionisation. Uranus was made. As one explores the museum, their analyses point instead to sulphur dioxide,
This lowers its altitude, altering the path of Herschel’s musical compositions can be heard which occurs in large quantities in Venus’ at-
radio signals in the 15–40kHz band. Moni- continuously in the background. mosphere. A study by Cornell University in
toring the signal strength of a transmitter in The contribution that William, Caroline 2021 July has alluded to volcanic activity as
this part of the spectrum allows the flare to be and John (William’s son, who continued their a cause. But in contrast, a re-analysis of data
recorded as a sudden ionospheric disturbance work) made to astronomy is hard to overstate. from the Pioneer Venus Multiprobe, which
(SID), the signal strength either rapidly in- As Michael Lemonick, a science writer, com- visited the planet in 1978, tentatively supports
creasing or decreasing according to the actual mented: ‘As a musician, Herschel was unusual- the presence of phosphine, although it cannot
path involved. ly talented. As an astronomer, he was a genius.’ confirm it. This study suggests that other ▶

J. Br. Astron. Assoc. 132, 1, 2022 11
Notes & News

▶‘biologically relevant chemicals’ in the Ve- Dr David Arditti, Director, Equipment & 400 light-years. It was given the nickname
nusian atmosphere appear to be in a state of Techniques Section: ‘the Intergalactic Wanderer’ when it was er-
disequilibrium: another hallmark of life. roneously thought not to be in orbit around
So the jury is still out. Forthcoming mis- 12. Jesse Ramsden (1735–1800) invented the Milky Way. (Harlow Shapley also coined
sions to Venus may solve this enduring mys- the yoke-type equatorial mounting. What is the name ‘Intergalactic Tramp’.) However,
tery. What is in agreement is how little is the name of the first telescope so mounted? although at a distance of 275,000 light-years
actually known about the composition of Ve- The Shuckburgh Telescope. Ramsden built from our solar system (which is even farther
nus’ atmosphere. And there is a range of new this 4-inch equatorially mounted achromatic than the Milky Way’s largest satellite galaxies,
missions planned by Roscosmos, ISRO, ESA refractor for Sir George Shuckburgh-Evelyn, the Small and Large Magellanic Clouds), it is
(its EnVision mission plus JUICE, which will for installation at Shuckburgh Hall, Lower still gravitationally bound to our galaxy, and is
make a flyby of Venus on its way to Jupiter) Shuckburgh, Warwickshire. It was ordered in thought to complete one highly eccentric orbit
and two NASA missions, set to launch in 2028 1781, but not completed until 1793. After Sir every three billion years.
and 2030. Even a private company, Rocket George’s death in 1804, it was moved to the
Lab, is working with the Massachusetts Insti- Royal Observatory, Greenwich, where it was 15. NGC 2264 unusually identifies two ob-
tute of Technology to send a small probe into known as the Eastern Equatorial. Equipped jects – what is the common name (topical
Venus’ atmosphere. Whatever they find, the with a micrometer by Dollond, it was used to for the festive season) of one of them? The
discovery of phosphine has increased inter- observe the 1832 transit of Mercury; the ob- Christmas Tree Cluster. NGC 2264, located
est in what some scientists have considered server at this time noted how the black-drop in the Monoceros constellation (the unicorn)
Earth’s forgotten sister planet. effect was prominent. In 1835 it was used to about 2,600 light-years from Earth, identifies
observe Halley’s Comet, and in 1929 it was two objects: the Cone Nebula and the Christ-
9. Who wrote quotes (a), (b), (c) and (d)? given to the Science Museum, London. mas Tree Cluster. (Two other objects are with-
(a) Arthur C. Clarke. (b) Richard Feynman. in this designation but not officially included:
(c) Stephen Hawking. (d) Carl Sagan. 13. Which two elements take their names the Snowflake Cluster and the Fox Fur Nebu-
from dwarf planets in the solar system and, la.) The Christmas Tree Cluster, which can be
when combined, describe the colour of a seen with binoculars, was named for its trian-
Dr John Mason, Director, Meteor Section: great spot on Jupiter? Plutonium and cerium, gular shape, formed by a cluster of very young
named after Pluto and Ceres. Their chemical sparkling blue stars that resemble a Christmas
10. Which two annual meteor showers are symbols respectively are PU and CE, giving the tree. William Herschel discovered the cluster
associated with dust from comet 1P/Halley? adjective ‘puce’. in 1784, and then went on to discover the neb-
The Eta Aquariids, active in late April/early Plutonium is a radioactive metallic element ula on Boxing Day in 1785.
May, and the Orionids, in late October. The which is created in reactors when uranium atoms
Eta Aquariids occur near the descending node absorb neutrons. First synthetically produced by 16.What number links (a), (b), (c) and (d)?
of the comet’s orbit (which is retrograde), the University of Berkeley in 1940/’41, it was 20.
while the Orionids occur near the ascending named plutonium since it was the next element (a)Père Lachaise Cemetery, 20th arrondisse-
node. Together, the two meteor showers are to be discovered on the periodic table after ura- ment of Paris. Charles Messier is famous for
sometimes dubbed ‘the Halley-ids’. nium, which had been named after the planet cataloguing over 100 nebulae and faint star
Uranus, and neptunium, after Neptune. How- clusters, discovered by chance when hunting
11. Which major annual meteor shower was ever, because of wartime secrecy, the discovery for comets. He is perhaps the most famous
apparently not recorded before the early could only be published in 1948. French astronomer, and an asteroid and two
1830s? The Geminids. This shower, which Cerium is a soft, silvery-white metal dis- lunar craters are named after him. He died in
peaks in mid-December, was first noted in the covered in 1803 by Jöns Jacob Berzelius and 1817 and was buried in Père Lachaise Cem-
early 1830s but the early displays were not Wilhelm Hisinger in Sweden, and independent- etery. With over 3.5 million visitors each
noteworthy, with only 10 to 20 meteors seen ly in the same year by Martin Klaproth in Ger- year, this is the largest cemetery in Paris
per hour. Since that time, the Geminids have many. It was named by Berzelius after the as- and Messier is in good company, laid to rest
grown in importance to become the most ac- teroid Ceres, discovered two years earlier. (The with Frédéric Chopin, Georges Bizet, Maria
tive of all the regular annual meteor showers. asteroid itself is named after the Roman goddess Callas, Molière and Jim Morrison.
At its peak, up to 120 Geminid meteors can of agriculture and fertility.) Cerium today has a (b) The nebula is catalogued as M20. Discovered
be seen per hour under perfect viewing con- variety of uses and cerium(IV) oxide has an im- by Messier in 1764, it is a bright, star-forming
ditions. The shower is associated with debris portant role in catalytic converters. nebula located about 3,000 light-years from
from 3200 Phaethon (an asteroid or a possible Ceres and Pluto were both reclassified by the Earth in the constellation Sagittarius. Its
‘rock comet’). IAU as dwarf planets in 2006. common name, the Trifid Nebula, means
‘three lobes’ and it consists of three bands of
obscuring interstellar dust. It can be viewed
Callum Potter, Director, with binoculars or a telescope.
Deep Sky Section: (c)Approximate distances from Earth in
light-years: alpha Centauri, 4.36; Barnard’s
14. What type of object is Star, 5.96; Ross 154, 9.68. The alpha Cen-
the Intergalactic Wanderer? tauri system comprises alpha Centauri A and
Globular cluster. NGC 2419 B, which form a binary pair, and proxima
(also known as Caldwell 25) is Centauri, a red dwarf. These stars are the
in the constellation Lynx and closest to Earth, but using current technol-
was discovered by William ogy, reaching their Earth-sized planets would
Herschel on New Year’s Eve take over 6,000 years. Barnard’s Star lies in
in 1788. Messier missed this Ophiuchus (the serpent holder) and is named
10th-magnitude object, but after the American astronomer E. E. Barnard.
it lies within reach of a small It is the second-closest star (if one consid-
telescope. It is actually a huge, ers the alpha Centauri triple system as one
Charles Messier’s grave in Père Lachaise Cemetery, Paris (see highly luminous cluster with star). It is too faint to see with the naked eye,
Q.16). (Marie-Louise Archer) one million stars, spread across with an apparent magnitude of +9.5, but it

12 J. Br. Astron. Assoc. 132, 1, 2022
Notes & News

has an allure: it has the largest proper motion This dramatic view of Io shows two simultaneous-
of any known star and is hence also known ly occurring volcanic eruptions. One can be seen
as Barnard’s Runaway Star. It is one of the on the limb (top left), where ash clouds are rising
300 kilometres above the satellite’s surface. The
most studied red dwarfs. Ross 154 is another
second can be seen on the terminator (shadow be-
red-dwarf star, in the southern constellation tween day and night), where the volcanic cloud
of Sagittarius. It has an apparent magnitude is catching the rays of the rising Sun. The dark
of +10.44, so is much too faint to be seen hemisphere of Io is made visible by light reflected
with the naked eye. from Jupiter. This is the actual image that Linda
(d) The RBS polymer £10 bank note features Morabito used to discover the first-known volca-
Mary Somerville. She was a mathemati- nic eruption on Io. (NASA/JPL)
cian, scientist, astronomer, geographer, and
a gifted science writer at a time when wom-
en’s participation in science was discour-
aged [a full article on her will soon appear in Voyager 1 was already
the Journal]. on its way to Saturn
when Morabito anal-
ysed images of Io taken
by the probe when it
was 2.6 million miles One of the most spectacular images taken

away from the moon, by Voyager 1 of Io (at a range of 400,000km),
three days after its historic showing the two great volcanoes Pele (centre
flyby of Jupiter. She almost right) and Loki (upper left). (NASA/JPL)
did not turn up for work on 1979
Mar 9, as the tasks ahead were not urgent, and
she was suffering from severe lack of sleep af- Rev Martin Davidson. (b) Four: the Rev
(Reproduced by kind permission of the Royal Bank of Scotland © 2022)
ter three tumultuous days. However, when she Flamsteed, Rev Bradley, Rev Bliss and Rev
scrutinised one of the images that day, she made Maskelyne. (c) Four: the Rev Robert Main,
one of the most remarkable discoveries in as- Rev John Brinkley, Rev Charles Pritchard and
Bob Mizon, Coordinator, Commission for tronomy: a 190-mile cloud off the side of Io. Rev T. E. R. Phillips.
Dark Skies: Every possibility was considered, until only one
explanation remained – she had discovered the 21. What caused Johann Franz Encke’s
17. In which English national park is the first-known extraterrestrial volcanic eruption. 55th birthday party to be interrupted?
International Dark Sky Reserve known Before the mission, images of Io were limit- Encke was director of the Berlin Observatory.
as ‘Moore’s Reserve’? South Downs Na- ed. Viewed from Earth, the moon remained just His 55th birthday was on 1846 Sep 23. Around
tional Park. The Park covers an area of chalk a point of light until the early 20th century, and midnight, Johann Galle (assistant director)
downland spanning 140km across southern telescopic observations in the mid-20th century and Heinrich d’Arrest interrupted the party to
England, stretching from St Catherine’s Hill only hinted at Io’s unusual nature. announce that they had found ‘a star, not on
near Winchester in the west, to Beachy Head Io is slightly larger than our own Moon and the map’ just over a degree away from where
in the east. Juxtaposed between the expand- is about the same distance from Jupiter as the Urbain Le Verrier predicted there would be a
ing, light-polluted urban areas of London and Moon is from Earth. There was every expecta- trans-Uranian planet. They had found Neptune.
the towns on the South Coast, it is remarkable tion that the satellite would be reminiscent of
how the Park maintains its dark skies. In 2016 our Moon, with a cratered, geologically inactive 22. What trait is shared by Edwin Hubble,
May it became an International Dark Sky Re- surface. But this could not have been further Sir Patrick Moore, the Rev T. E. Espin
serve and was named ‘Moore’s Reserve’ in from the truth! Io is the most active volcanic and Dr Allan Chapman? Their love of cats.
memory of Sir Patrick Moore, who lived local- world in the solar system, the result of tidal heat- There has always been a fascination and link
ly at Selsey. Within the International Dark-Sky ing from friction generated within its interior as between astronomers and cats: whether this
Association’s worldwide scheme of certified it is pulled between Jupiter and the other Gali- is because cats are nocturnal creatures, or be-
Dark Sky Places, Britain is fortunate in hav- lean moons. Its volcanic plumes and lava flows, cause they embody qualities and personality
ing more of these (seven so far) in relation to some more than 500 miles in length, paint the traits with which astronomers are able to as-
its size than any other nation outside the USA. surface in various shades of black, orange, yel- sociate, is not known. But many famous as-
low and blue, caused by sulphur dioxide at vari- tronomers have expressed their love of cats,
18. Which famous astronomer is co-chair of ous temperatures (Io is affectionally described as have many members of the BAA Council.
the All-Party Parliamentary Group (APPG) by NASA scientists as a mouldy pizza). The Dr Allan Chapman has written about this asso-
for Dark Skies? Lord Rees, the Astronomer young surface has no obvious impact craters. ciation in his excellent book Comets, Cosmol-
Royal. The APPG of MPs was founded in Following the plume discovery, the volcano ogy and the Big Bang: A History of Cosmology
2020, with the support of the BAA Commis- which produced the emission was named Pele from Edmond Halley to Edwin Hubble (Lion
sion for Dark Skies, the CPRE and others, by the IAU, after the Hawaiian volcano god- Hudson, 2018).
to press the government to adopt dark-sky dess. Pele is notable for a persistent, large red
policies ( ring circling the volcano due to sulphurous fall- 23. Which solar-system body is linked to Eas-
Currently, the night sky has no protection out from the plume. But it is thought to be one ter, and has a satellite discovered in 2015?
whatsoever in law. of over 400: Io is a true volcanic wonderland. Makemake. This dwarf planet was discovered in
2005 by Mike Brown and his team at the Palo-
19. Who first discovered that Jupiter’s moon mar Observatory, and they code-named it ‘East-
Io was volcanic? What links this to the Ha- Mike Frost, Director, Historical Section: erbunny’, as it was discovered just after Easter.
waiian Goddess of Fire and a famous Brazil- In accordance with IAU rules, it was given the
ian footballer? Linda Morabito (a.k.a. Linda 20. How many (a) BAA presidents (b) As- name of a creator deity – Makemake is the cre-
Morabito-Meyer), part of the NASA Voyager tronomers Royal and (c) presidents of the ator of humanity and fertility god of the Rapa
navigation team. The first volcano discovered RAS were ordained? (a) Three: the Rev Nui people of Easter Island. At 45.8au from the
on Io was named Pele. T. E. R. Phillips, Rev C. D. P. Davies and Sun, it is even further away than Pluto. The ▶

J. Br. Astron. Assoc. 132, 1, 2022 13
Notes & News

▶ surface is of a reddish-brown hue; spectral
analysis has identified frozen methane and eth-
ane there. In 2015, using NASA’s Hubble Space
Telescope, a moon was discovered (nicknamed
MK 2), about 1,300 times fainter than its parent.
Makemake is also of significance as, along with
Eris, it was one of the objects whose discovery
prompted the IAU to re-classify Pluto and create
a new group of dwarf planets.

Sandra Brantingham, Director, Aurora
& Noctilucent Cloud Section:

24. It was once thought that the aurora were
reflections of sunlight off the polar ice cap.
Give a reason why this cannot be. In winter,
due to the tilt of Earth, the northern ice cap is McDonald Observatory, in Texas. (Ethan Tweedie Photography)
permanently dark.
common knowledge that a celestial body had 2,000m. For over 40 years, since the Apollo 11
25. Which Liverpudlian brewer built his own been named after someone’s pet. Ultimately, mission, the observatory aimed lasers at spe-
24-inch telescope and discovered four moons a committee of the International Astronomical cial reflecting mirrors (retroreflectors) left on
in the solar system? William Lassell. The son Union was set up that is responsible for nam- the lunar surface by Apollo astronauts, allow-
of a timber merchant, Lassell made his fortune ing small solar-system bodies, known as the ing the Moon’s distance to be measured with
as a brewer, but his passion lay in astronomy and Working Group on Small Body Nomenclature great precision. A total of five mirrors were
he became one of the leading Victorian astrono- (WGSBN). Pet names are now definitely off left at five sites on the Moon (including two
mers. His discoveries include Triton, the larg- limits. According to Jim and Ursula, Mr Spock by the Russian Lunokhod programme). These
est moon of Neptune; Hyperion (co-discovered the cat was ‘imperturbable, logical, intelligent, have shown that the Moon is moving away
independently with William Bond), a moon of and had pointed ears’ – just like his namesake! from Earth at about 3.8cm per year. Scientists
Saturn; and two satellites of Uranus: Ariel and have also used this information (along with
Umbriel. His 24-inch reflector was a revolution- 27. Why was a small canister predominantly measurements that continue to be made at
ary instrument as it was the first telescope with a of calcium phosphates placed in the New Ho- other observatories) to probe the Moon’s inte-
large mirror to be mounted equatorially to allow rizons probe? The canister contained some of rior, showing a molten outer core, and to study
easy tracking of the stars, and it paved the way the ashes of Clyde Tombaugh, who discovered Albert Einstein’s theory of gravity, among
for future developments in reflector technology, Pluto in 1930. New Horizons was the first probe other applications. Furthermore, the mirrors’
leading to the large equatorial instruments seen to fly past Pluto in 2015 and the capsule was car- existence, and the fact that astronomers can
in many observatories around the world. Lassell ried in homage to the planet’s discoverer. bounce lasers off them and detect the returning
also built a much larger, 48-inch telescope with Clyde Tombaugh had a distinguished astro- beams, has also provided compelling evidence
37-foot focus and used it in Malta. He was pres- nomical career. His discovery of Pluto, whilst to refute the claims of Moon-landing conspir-
ident of the Royal Astronomical Society from working at the Lowell Observatory in Flag- acy theorists.
1870 to 1872. staff, Arizona, was made when he was only The observatory is named after the banker
24, and involved comparing photographic William Johnson McDonald, who left most of
plates with a ‘blink comparator’ to spot signs his fortune to the University of Texas to build
Dr Richard Miles, Director, Asteroids & of moving celestial objects. The discovery re- an astronomical observatory. McDonald is
Remote Planets Section: shaped scientists’ understanding of the solar said to have thought that an observatory would
system, as Pluto was the first object to be dis- improve weather forecasting and thus help
26. Has an asteroid been NB
CT covered in what would later be identified as farmers to plan their work.
named after the Star the Edgeworth–Kuiper Belt. (At a banquet to

Trek character Mr celebrate the 50th anniversary of this discovery 29. What is the most likely reason that the

Spock? No. An in 1980, he commented that ‘I had no idea that earliest photograph of the Moon no longer
asteroid has been two little tiny black specks on some glass plates exists? Daguerre’s laboratory burnt down
named in honour of would cause this much of a rumpus!’.) But he in 1839.
Leonard Nimoy, the went on to discover a comet, hundreds of aster- Louis Daguerre was a French artist and
actor who played Mr oids and several galactic star clusters. Asteroid photographer who became famous in 1822
Spock in the Star Trek (1604) Tombaugh is named after him (and at the after inventing the daguerreotype, the earliest
television series, namely same banquet, when giving his thanks for the form of photography. On 1839 Jan 2, he took
asteroid (4864) Nimoy. There is an asteroid honour, he commented: ‘Now I have some real the first-ever photo of the Moon. It must be re-
(2309) Mr Spock, but this was named by Jim estate that nobody can touch!’). membered that up until this time astronomers
Gibson, who discovered the object in 1971 and were reliant on sketching what they saw in
who named it after a beloved cat of that name their telescopes, often missing crucial details,
belonging to his wife, Ursula. Both being Dr Tony Cook, Acting Director, Lunar and any reproductions made of these sketches
professional astronomers, their cat accompa- Section: could include errors and omissions. Daguerre’s
nied them on astronomical expeditions in the invention was groundbreaking, and though ex-
United States, South Africa, and Argentina. 28. Which observatory was involved with pensive, became hugely popular. However, in
When they submitted the name, they did not measuring the Moon’s distance and has March of that same year, his laboratory burnt
expect it to be accepted, and if it was, it would a restaurant chain as a namesake? The down and the photo of the Moon was lost. The
show that some formal mechanism should McDonald Observatory. This observatory is fire destroyed all his written records and much
be established to vet such names. Predict- part of the University of Texas at Austin and of his early experimental work. In 1839 June,
ably, there was rather a furore when it became has several telescopes, at an altitude of over the French government were given the rights

14 J. Br. Astron. Assoc. 132, 1, 2022
Notes & News

to the daguerreotype in return for Daguerre be-
ing awarded a lifetime pension. He was also
appointed an officer of the Légion d’honneur,
and his name is one of 72 inscribed on the Ei-
ffel Tower.

30. Name songs (a)–(e), all of which contain
in their titles the names of solar-system bod-
ies. (a) ‘Fly me to the Moon’ by Frank Sinatra.
(b) ‘Walking on the Moon’ by The Police (writ-
ten by Sting). (c) ‘Venus and Mars’ by Wings
(written by Paul and Linda McCartney). (d)
‘Venus’ by Lady Gaga. (e) ‘Life on Mars?’ by
David Bowie.

Lyn Smith, Director, Solar Section:

31. What solar feature is named after the
American astrophysicist Charles Hyder?
Why is it different to other similar features?
What is its main characteristic? The Hyder
flare. This is an intense brightening that is
not associated with an active region, occur-
Dr Frank Drake. (With kind permission of Seth Shostak/SETI Institute)
ring elsewhere within the chromosphere and
usually in connection with the disappearance
of a long, dark filament. The flare usually ap- The month of 2021 February was also a world. Entitled Solar Eclipse (1900), it can be
pears as bright spots alongside the filament, milestone for NASA, which on Feb 18 success- viewed online as part of the BFI Player’s Vic-
or bright ribbons running along one or both fully landed its nuclear-powered Perseverance torian Film collection.
sides of it as it lifts. The main characteristic rover (and Ingenuity helicopter) on Mars. It will
of Hyder flares is that they develop and rise search for signs of ancient microbial life, col- 34. What were the words first spoken by
to maximum brightness much more slowly lect rock and soil samples for a possible return Buzz Aldrin when he set foot upon the
than active-region-associated flares. Although to Earth, and test oxygen production to support Moon? ‘Beautiful view. Magnificent desola-
generally low in intensity and occurring over a human life in the future. tion.’ When Neil Armstrong stepped onto the
large area, they can last for several hours. Moon in 1969, his immortal words were for-
ever enshrined in history. But less well known
32. Why was the world’s tallest building il- Dr Richard McKim, Archivist & Director, is what Buzz Aldrin said. Aldrin, who was the
luminated in red on 2021 Feb 9, and why Mars Section: Lunar Module pilot, stepped onto the Moon’s
were there fireworks 6,000 kilometres to the surface only 19 minutes after Armstrong. The
east-northeast on the following day? The 33. Which early BAA member made the decision for Aldrin to follow Armstrong was
UAE’s Hope (‘Amal’) orbiter successfully en- first film of a total solar eclipse? The Rev made by NASA’s Director of Flight Crew Op-
tered orbit around Mars on 2021 Feb 9, followed John Mackenzie Bacon. The lost film refers erations, Donald ‘Deke’ Slayton and his team,
by China’s Tianwen-1 probe which reached the to footage taken by Bacon of the total solar noting that it was appropriate for the com-
red planet a day later. eclipse in India in 1898; unfortunately, on his mander to go first in view of the immensity of
The Burj Khalifa in the United Arab Emir- way back the film was stolen and its fate is un- the occasion, but this was controversial with
ates (828m in height) was illuminated in red known. Bacon used equipment developed by Aldrin, who had originally been told that he
to celebrate this first Arab spacecraft to reach John Nevil Maskelyne, who was a friend and would be stepping out first.
Mars. The probe aims to provide a complete collaborator of Bacon’s (and was a magician
picture of the Martian atmosphere and weather, by profession). In 1900, Maskelyne accompa- 35. Where, in 1961, did a male duck meet
studying daily and seasonal changes (it will nied Bacon on the BAA’s expedition to North with nine dolphins to create a famous equa-
not land). To develop and build Hope, Dubai’s Carolina where they filmed another total so- tion? What does the equation estimate? Dr
Mohammed Bin Rashid Space Centre worked lar eclipse. This 120-year-old film is held in Frank Drake (pictured above) organised a meet-
with US educational institutions. Hope’s arrival the RAS archives and has been restored by ing of astronomers and scientists at the National
at Mars coincided with the 50th anniversary of the British Film Institute. It is believed to be Radio Astronomy Observatory at Green Bank,
the founding of the UAE. the earliest surviving astronomical film in the West Virginia, in an attempt to estimate the
China’s Tianwen-1 (‘Questions to Heaven’) number of active, communicative civilisations
probe also took advantage of an optimal launch in our galaxy.
window in 2020 and reached Mars’ orbit a day In 1961 Drake, who is a renowned astro-
after Hope, on 2021 Feb 10. It includes an or- physicist, brought together a group of experts
biter, lander and a 240kg rover. Following a suc- from a range of disciplines who dubbed them-
cessful entry into orbit, the lander touched down selves ‘The Order of the Dolphin’ because of
on the surface of Mars on May 15 (making Chi- one member’s work on dolphin communication.
na only the third country to successfully land The meeting was convened following two no-
on the red planet). The Zhurong rover began its table pieces of research. Firstly, a paper in 1959
journey on the Martian surface on May 22. The by two physicists, Cocconi and Morrison, who
aims of the mission are multiple: to investigate argued that radio telescopes could detect trans-
the geological structure of Mars, search for indi- Still frame from John Nevil Maskelyne’s footage missions from alien civilisations transmitted at
cations of current or past water and life, and also of a solar eclipse on 1900 May 28. (Royal Astro- a wavelength of 1420.4 MHz (hydrogen), which
study the Martian atmosphere. nomical Society) they thought might be a logical ‘landmark’ ▶

J. Br. Astron. Assoc. 132, 1, 2022 15
Notes & News

▶ because hydrogen is the most common ele- Mike Foulkes, Director, Saturn, Uranus & On 1905 Apr 28, William Henry Pickering,
ment. Secondly, Drake’s own work on Project Neptune Section: an American astronomer who had discovered
Ozma, which was the first systematic attempt to Saturn’s moon Phoebe in 1899, announced
detect artificial radio signals from nearby stars. 36. Who is the odd one out from this list? he had discovered a tenth satellite which he
The Drake equation (also called the Green François Arago, William Lassell, John named ‘Themis’. For this discovery he was
Bank equation) states: Couch Adams, Johann Galle, George awarded the Lalande Prize of the French
Biddell Airy, Urbain J-J. Le Verrier. All Academy of Sciences in 1906. However, the
N = R*  f P ne  f l  f i  f c  L have had a ring of Neptune named after them moon was never seen again, and no other
except George Biddell Airy. astronomer has ever confirmed Pickering’s
where N is the number of civilisations that we Sir George Biddell Airy was a mathema- claim (although it appeared in almanacs and
could communicate with, R* is the mean rate tician and astronomer who was Astronomer astronomy books well into the 1960s).
of star formation, fP is the fraction of stars with Royal from 1835 to 1881. His achievements The actual tenth satellite of Saturn (in order
planets, ne is the mean number of habitable are numerous, including his work on planetary of discovery) is Janus, which was discovered
planets per exoplanetary system, fl is the frac- orbits, his transformation of the Royal Ob- in 1966 and confirmed by Voyager 1 in 1980.
tion of habitable planets on which life develops, servatory at Greenwich into a major research It is one of the innermost moons of Saturn
fi is the fraction of fl with intelligent life, fc is the institution and establishing Greenwich as the (whereas the supposed orbit of Themis lay be-
fraction of intelligent civilisations that develop location of the Prime Meridian on which GMT tween Titan and Hyperion).
communication and L is the mean length of time is based.
for which they can communicate. Airy also had a role in the discovery of Nep- 38. Which 1995 book explores the imaginary
All these factors are conjectural, with values tune. This planet was found by Johann Galle science of the TV series Star Trek? Who was
ranging over many orders of magnitude. But on 1846 Sep 23 at the Berlin Observatory. His the author, and what did he say warps when
Drake stressed that the equation was not a seri- search was based on predictions submitted you travel at warp speed? The Physics of Star
ous attempt to determine an exact number but a to him by the French astronomer Urbain Le Trek by Lawrence M. Krauss. Spacetime is
framework for research, bringing together fac- Verrier and it was found within one degree of warped when travelling at warp speeds.
tors which scientists should consider when pos- Le Verrier’s predicted position. These predic- Gene Roddenbury, the series creator, was de-
tulating the chances of extraterrestrial life. tions were known to Airy, as were those made termined that the show would be as technically
Over the last 60 years, there have been re- by John Couch Adams, an undergraduate at accurate as possible and he thus sought advice
finements to this equation following devel- Cambridge, in 1845. Following the discovery, from physicists and a research company; Isaac
opments such as the discovery of exoplanets Airy was severely criticised by a number of his Asimov even volunteered his thoughts.
(although the L parameter is still completely contemporaries for not acting to ensure it was The book looks at several technological phe-
unknown). This has been accompanied by the made by a British astronomer. nomena in the series. Many of these have come
burgeoning work of SETI (Search for Extrater- Some historians have subsequently de- to pass: tablet computers, replicators, voice
restrial Intelligence) which has concentrated on fended Airy’s role. Today, both Adams and Le interface computers, bluetooth headsets, GPS,
receiving and analysing signals from space, par- Verrier are often given a share in the credit of automatic doors and teleconferencing, to name
ticularly in the radio and visible-light regions of having predicted the existence and position of a few. Even warp propulsion (generating warp
the electromagnetic spectrum, and looking for Neptune. However relatively recently, some fields to envelop a starship in a subspace bubble
non-random patterns likely to have been sent by historians have argued that this achievement to distort spacetime, and so propel it at a veloc-
technologically advanced beings. should be credited to Le Verrier alone. ity faster than the speed of light) is a concept
Drake, who spearheaded this work and No ring of Neptune was named after Airy, which NASA has studied. The series was also
helped found the SETI Institute in 1984, cel- but he was honoured with the naming of a ahead of its time in creating a multiracial, multi-
ebrated his 91st birthday in 2021 May and con- lunar crater. cultural and gender-diverse environment.
tinues to be optimistic about a ‘close encounter’. But perhaps of particular note is that the Star
He feels this will enrich our civilisation, since 37. In 1905, an astronomer announced Trek phenomenon brought the wonders of sci-
he considers altruism a Darwinian characteristic the discovery of a tenth satellite of Saturn ence and technology into everybody’s living
which would be present in extraterrestrial life. which was later found not to exist. Name room. As Krauss commented, ‘the real universe
He has even postulated that we could use stars the astronomer and the satellite. The as- is even more fascinating than the world of sci-
as gravitational lenses to detect alien life, which tronomer was named W. H. Pickering and the ence fiction, but science fiction sparks people’s
has been shown to be technically possible. satellite was called Themis. imagination’.

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and worldwide of all types of observable objects, together with dis-
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16 J. Br. Astron. Assoc. 132, 1, 2022
Notes & News

Asteroids & Remote Planets Section (Occultations)

Double star unexpectedly detected during
occultation by asteroid – a first from the UK
SER format) should be time-stamped via
These results are a very dramatic demonstration a dedicated GPS receiver or a computer
of the effectiveness of the occultation method at clock carefully synchronised to Universal
measuring the intrinsic properties of a double star Time.2 Event timings can be displayed in
or occulting body. – R. Miles, Director Tangra and several stars can be selected
for comparison purposes.

M any asteroids are predicted to occult stars
each year, but only a tiny fraction of these
events are visible from any one location on
The recording of this observation in-
volved the use of a WAT-910HX video
camera together with a GPSBOXSPRITE3
Earth. One such event involved the main-belt time-inserter, a USB video digitiser and
asteroid (212) Medea, which was predict- VirtualDub video-capture software.
ed to occult the magnitude 10.3 star TYC
1857-01108-1,1 in Taurus, on the evening of
2021 Nov 23 (See the 2021 BAA Handbook, What does the light curve reveal?
page 56).
Philip Denyer was observing from Horn- Note that the first D–R event did not to-
church, London that evening using a Celestron Figure 1. The predicted shadow path for (212) Medea. tally extinguish the star as would normally
C9.25 Schmidt–Cassegrain telescope equipped (E. Goffin) be expected: some light remained. Then,
with a WAT-910HX integrating video camera, the second D–R event exhibited a drop in
when an unusual event was about to unfold. Phil curve was produced using Tangra software. intensity amounting to about half that of the first
was making a routine observation in the hope [In Table 1] are my times and event details step-change in brightness.
of seeing an occultation, which occurs when the as extracted by visual inspection of the The rapidly fluctuating light levels are caused
light from the star is obstructed by the passage light curve [see Figure 2]. A quick look at by turbulent seeing conditions in our atmosphere
of the asteroid body blocking it for a few sec- the light curve shows the magnitude drop and changes in transparency. Given the short ex-
onds. However, it turned out that the star ‘blink- on second D [‘disappearance’] appears to posure time used, the observed fluctuations are
ed’ not once but twice. be about half the level of the first D.’ similar to the appearance of stars ‘twinkling’.
In his initial communication to the Asteroids The effect can be smoothed out to a degree by
& Remote Planets Section (ARPS), Phil wrote: placing the star slightly out of focus.
Obtaining a light curve The observation by Phil is a very clear-cut
‘I obtained a positive result of (212) Medea and dramatic demonstration of each component
on November 23rd. I saw on the monitor a The ARPS Occultations group recommends of the double star passing along separate chords,
dip two seconds before the predicted time the use of video or CMOS cameras to record traversing behind the solid body of the asteroid.
for my location. However I did not notice potentially occulted stars over an interval of a Sadly, no other observer has sent in a report of
a second dip on the monitor until the light few minutes. The digital recording (in AVI or this occultation, either positive or negative. ▶

Table 1. Occultation timings, by Philip Denyer
The first D (predicted time 22:36:31 UT; offset error 2s; max. duration 13.7s; mag. drop
2.1) was followed by a gap of 29.72 seconds and then the second D:

Disapp. (UT) Reapp. (UT) Duration (s)
First D 22:36:34.579   5.68
Second D 22:37:04.299 12.04

Figure 2. Light curve obtained by the observer using Tangra (author: Hristo
Pavlov). The yellow trace is the measured intensity of a brighter star used
to simultaneously monitor the seeing conditions and transparency. The blue Figure 3. report for the double-star occultation observed by Phil Denyer.
trace is the intensity of the occulted star + asteroid vs. time. (P. Denyer) (E. Frappa)

J. Br. Astron. Assoc. 132, 1, 2022 17
Notes & News

Solar Section
Lyn Smith

2021 October

A lthough activity fell com-
pared to the preceding
month, it was still relatively high, with the
Relative sunspot number (R) being the second-
highest recorded by the Section since 2017
September. The Quality number also fell, but
nevertheless remained at a comparatively high
level. Twelve sunspot groups were recorded,
with groups being observed on all days of the
month except Oct 17, when most observers re-
corded a blank disc.

AR2877 S21°/328° remained on the disc from Left: The Sun in H-alpha on 2021 Oct 6 at 09:15 UT, imaged from Preston, Lancashire. (Stuart Green)
the previous month but was approaching the Right: Active Region 2882 on 2021 Oct 9. (Brian Halls)
SW limb on Oct 1, type Dao. The group then
rotated around the limb.
sunspot. On Oct 13, only one faint sunspot AR2887 S26°/277° appeared over the SE limb
AR2880 N32°/244° also survived on the disc was seen preceding the main element. The on Oct 22 and proved to be the largest and
from the previous month, midway across the group was last seen on Oct 16, close to the most active group of the month. Although ini-
NE quadrant. The group was bipolar and type NW limb. tially a single penumbral sunspot of type Hsx,
Dac, consisting of a penumbral leader and the group was fully on the disc the following
two smaller followers, with an area of around AR2883 N27°/203° was a faint Axx sunspot day and comprised of two penumbral sun-
310 millionths. It crossed the central meridian that formed in the NW quadrant on Oct 10 and spots in a roughly east–west alignment, with
(CM) during Oct 3/4 and during its passage, was still present on Oct 11, nearing the limb. two smaller penumbral sunspots to the south.
several pores were noted between the leader A pore was also seen to the north-west of the
and follower sunspots. The group was last AR2884 S20°/170° was another faint Axx-type following penumbral sunspot. Faculae were
reported on Oct 6, type Axx, in the NW quad- sunspot that formed in the SW quadrant on noted with the group from Oct 22 to Oct 25.
rant and approaching the limb. Oct 10 and was still present on Oct 11, but On the latter date it was seen to comprise of
faded thereafter. three penumbral sunspots spread out in lati-
AR2882 N18°/158° appeared over the NE limb tude, together with many pores. The penum-
on Oct 4, type Hsx; it was a single penumbral AR2885 N15°/171° appeared on the disc on bral areas of both the main leader and fol-
sunspot. This group showed little develop- Oct 14, close to the NW limb and west of the lower spots were highly asymmetric, and the
ment as it crossed the disc, but on Oct 6 sev- approaching AR2882. group had an area of 520 millionths. Although
eral pores were noted following the main sun- it reduced in size over subsequent days, it re-
spot, which had an area of 330 millionths. By AR2886 S18°/335° rounded the SE limb on mained a complex Dac group, with changes
Oct 9, the trailing sunspots were now located Oct 18. This was another sunspot that showed visible each day. The biggest change occurred
to the north of the main sunspot and it devel- little development as it crossed the disc, being between Oct 28 & 30, when there was a re-
oped into a type-Dko group on Oct 10 & 11, type Hax for most of its passage and having duction in the number of sunspots within the
with the total area measuring 360 millionths a maximum area of 180 millionths on Oct 20. group. It was clearly fading on Oct 31.
on Oct 11. By Oct 12, the fringe sunspots had The group crossed the CM on Oct 25 and was
started to fade and rotate to proceed the main last seen near the SW limb on Oct 29. AR2888 S15°/253° appeared over the SE limb
on Oct 25 as a faint Axx-type group that soon
faded on the disc.
Asteroids & Remote Planets Section (Occultations): Cont’d
AR2889 S25°/248° was preceded by faculae
▶ Reporting Star Catalogue and could represent a new de- on Oct 25 before the faint sunspot appeared
tection. Further investigation is suggested. on Oct 26. This developed into a collection of
An extract of a preliminary report on the Euraster small pores later that day, type Bxo. The group
website maintained by Eric Frappa is shown in Phil Denyer,Tim Haymes & Richard Miles remained Bxo on Oct 27 but faded again the
Figure 3 (see previous page).3 Eric helped with Asteroids & Remote Planets Section following day, dissolving on the disc.
the analysis and he details the magnitude of the
stellar components as A: 10.8 and B: 11.5, ob- 1 Prediction: The star is also known AR2890 S19°/317° formed on the disc on
tained using the Python program PyOTE.4 as UCAC4 593-016335. Oct 26 in the SW quadrant, to the east of
Given the motion of the asteroid at the time 2 Haymes T., ‘Observing asteroid occultations with AR2886. The group was type Cro but it
amounted to 0.47arcsec/min in position angle digital cameras’: reduced to type Bxo on Oct 27; it was still evi-
265°, we suggest an approximate separation of 3 Euraster: dent on Oct 28 but faded from view thereafter.
0.3 arcseconds between components A and B of 4 PyOTE is an occultation timing extraction utility,
the double. Surprisingly, the apparent double written by Bob Anderson of the International Oc- AR2891 N18°/211° appeared over the NE
star is not included in the Washington Double cultation Timing Association (IOTA). limb on Oct 27, type Cao, with a penumbral

18 J. Br. Astron. Assoc. 132, 1, 2022
Notes & News

leader and two small followers. The group Bipolar magnetic regions, filaments & plage
underwent rapid development once fully on BAA sunspot data,
the disc and it became a small, complex Dso 15 observers reported a filament MDF of 4.14 2021 October–November
group by Oct 30, with an area of 200 mil- and 14 observers reported a plage MDF of 2.11
October November
lionths. The group remained substantially un- for October.
Day g R g R
changed on Oct 31. On Oct 3, a curved filament was seen in
the southern hemisphere extending for about 1 2 27 3 42
AR2893 N16°/156° appeared on Oct 31 close to 100,000km. A string of magnetic regions, also 2 2 26 3 35
the NE limb, type Hsx. in the southern hemisphere, revealed a wealth 3 1 21 2 26
of detail. Supergranulation-cell structure in 4 2 25 2 23
20 observers reported a Quality number of Q = the conjoined pair of bipolar magnetic regions 5 2 23 3 29
5.68 for October. in the SE quadrant was spectacular. This pair 6 2 19 2 27
spanned about 350,000km east–west. Also, a 7 1 12 2 26
8 1 16 3 31
bright cluster of supercells were noted just west 9 1 20 3 33
of the CM, within a decayed bipolar magnetic 10 2 27 3 39
H-alpha region (BMR). 11 2 20 3 24
A faint filament was seen to bisect AR2880 in 12 1 14 2 27
Prominences the NW quadrant on Oct 6, aligned north–south. 13 1 15 2 22
On Oct 21 considerable chromospheric 14 1 14 2 19
19 observers reported a prominence mean daily structure, mainly comprising supergranulation 15 1 10 2 20
frequency of 4.81 for October. cells, was noted within a BMR that was SW of 16 1  8 3 28
Plage was reported with ARs 2882, 2880, AR2886 in the SE quadrant. Supergranulation 17 0  1 2 24
18 1 10 2 19
2882, 2886, 2887, 2889 & 2891. Extensive was also clearly seen in the BMR approaching 19 1 10 2 20
plage was seen in association with AR2887 on the meridian in the NE quadrant, and in a weak- 20 1 10 2 18
Oct 30. ening BMR just past the meridian in the NW 21 1 13 2 19
Prominence activity on the SW limb was ob- quadrant. A filament was seen trailing an area of 22 2 26 2 19
served on Oct 1, with a large arch prominence plage close to the NE limb and another trailed 23 2 35 2 21
rising to a height of around 50,000km, with a AR2886 in the SE quadrant. 24 2 31 2 27
width of about 65,000km. On Oct 22 a broad triangular filament was 25 3 48 1 20
On Oct 6, a large pyramid-shaped prominence seen in the NW quadrant, not far from the limb. 26 4 62 2 30
was on the NE limb, with a smaller flame-type On Oct 25, a north–south-aligned filament 27 4 69 2 33
28 4 67 3 37
prominence noticeable on the SW limb. trailed AR2887 in the SE quadrant. 29 3 59 3 33
A pillar prominence rose to a height of around AR2887 was active on Oct 28, with a very 30 3 52 4 48
80,000km on the SE limb on Oct 9. Small, de- active filament associated with the group. Ini- 31 2 34
tached plasma clouds were visible on the north- tially the filament appeared as a very thin hook
ern and SW limbs on Oct 10. in shape, but the middle section darkened and MDFg   1.98 (48)   2.39 (47)
On Oct 12, two bush-type prominences were thickened through time. Mean R 29.34 (44) 31.62 (43)
seen together on the SW limb, and they were
both still present as a distinctive hearth on
Oct 13. CaK North & south MDF of active areas g
A tree-like prominence was on the SW limb MDFNg MDFSg
on Oct 16 & 17. During the month, activity was seen in the October 0.92 (39) 1.10 (39)
Prominence activity increased on Oct 22 on southern hemisphere between latitudes S30° to November 1.21 (36) 1.19 (36)
the SE limb, with a large prominence remain- S40°, mainly between Oct 9–16 but not associ-
ing for several days, changing shape and extent ated with any visible sunspot groups. g = active areas (AAs)
throughout. CaK MDF 3.21 (1 observer, 19 days). MDF = mean daily frequency
R = relative sunspot number
A notable low arch prominence was seen
on the E limb on Oct 24, adjacent to the ap- The no. of observers is given in brackets.
proaching AR2887. By Oct 25/26, the arch had Flares
morphed into a low mound.
On Oct 26, a large eruption was reported on Mick Nicholls recorded a B1-type flare in as- AR2887 S27°/276° was much reduced from its
the NE limb, reaching an approximate height of sociation with AR2882 on Oct 6 at 09:46 UT; peak the previous month and was approach-
233,000km and stretching across the limb for Monty Leventhal reported a type-4 flare on ing the SW limb on Nov 1. The group had
about 251,000km. Oct 25, peaking at 21:10 UT and still active at rotated around the limb by Nov 3.
Prominence eruptions on both the NE 06:00 UT on Oct 26; Andy Devey reported an
and NW limbs were estimated to be around X1-flare on Oct 29 at 15:30 UT. AR2891 N17°/211° also survived on the disc
52,000km hight on Oct 27 and detached plasma Flares were also reported by Derek Glover, from the preceding month and was approach-
clouds were also reported hovering above the Andrew Johnson and Peter Meadows. ing the CM in the northern hemisphere on
E limb in the general vicinity of AR2891. Nov 1, type Dai. By Nov 3, the group had
The following day, a very tall but faint spike reduced to type Cao with an area of 90 mil-
prominence was seen on the NW limb, estimat- lionths. It was type Hax on Nov 4. By Nov 5,
ed to just exceed 175,000km in height. 2021 November the group had decayed to type Bxo; it was
On Oct 29, a platform-arch-type prominence type Axx on Nov 6 and was not seen on
was reported on the SW limb, rising to about White-light activity increased slightly over fig- Nov 7.
40,000km and with a width of 75,000km. ures recorded for October, with activity quite
The month closed with a detached column equally distributed over both hemispheres. The AR2893 N17°/155° survived on the disc from
prominence on the NE limb, rising to some- Quality number was also slightly up on the pre- the preceding month, still fairly close to the
where between 140,000 and 150,000km on vious month, with activity being recorded on all NE limb on Nov 1 and type Hsx. By Nov 3,
Oct 31. days of the month. the group was recorded as type Hax with ▶

J. Br. Astron. Assoc. 132, 1, 2022 19
Notes & News

▶ an area of 210 millionths; it was of similar AR2901 N18°/154° rotated over the NE limb on An extended and slightly curved spike promi-
appearance on Nov 4 when it was midway Nov 28 as a small Hsx sunspot group and had nence was recorded on the N limb on Nov 9, and
across the NE quadrant. This proved to be a an area of 50 millionths on Nov 29. The group a hearth consisting of three small elements in a
very stable sunspot. It continued its progress remained unchanged in the NE quadrant at broken-arch configuration was on the NE limb.
across the northern hemisphere unchanged the end of the month. A large pyramid-type prominence was the
and was just short of the NW limb on Nov 12. most significant seen on Nov 17.
A small light bridge at the north end of the AR2902 N18°/196° developed on the disc just On Nov 18, an unusual, flattened loop promi-
umbra was reported on Nov 3 and multiple east of the CM on Nov 30, type Bxo, with nence was seen on the SE limb. Although less
photospheric bridges were recorded crossing four sunspots reported. than 30,000km in height, it extended north-
the umbra of this unipolar sunspot on Nov 7. wards parallel to the limb from its vertical jet for
AR2903 S17°/148° developed on the disc on over 140,000km. The prominence had started to
AR2894 S28°/093° was reported over the SE Nov 30, not far from the SE limb and consist- break up by the following day but was still an
limb on Nov 5, type Hsx. This was another ing of two faint sunspots, type Bxo. interesting feature on the limb.
quite stable sunspot that changed little during At the south pole on Nov 22, a pyramid prom-
its progress across the disc, although a col- 19 observers reported a Quality number of Q = inence reached up to about 40,000km and on the
lection of small spots was seen following the 6.59 for November. SW limb another column prominence obtained
penumbral leader on Nov 7. Light bridges a similar height, but with plasma stretching
traversed the main penumbral sunspot on out from the top for about 100,000km around
Nov 11 & 16, with following faculae noted the limb.
on the latter day and an area of 210 millionths H-alpha On Nov 28 a curtain prominence was on the
recorded on the former. The group was last SE limb, comprising five tree-like elements. On
seen close to the SW limb on Nov 17. Prominences Nov 29 a loop prominence was on the SW limb,
extending for some 10° along it.
AR2895 N24°/093° formed over the NE limb 16 observers reported a prominence MDF of
on Nov 7, initially as faculae. By Nov 8, a 4.61 for November.
mature sunspot group had emerged. On Nov 9 On Nov 1, a column prominence rose to about Bipolar magnetic regions, filaments & plage
the group was classified as type Dao, with an 120,000km on the SE limb and another simi-
area of 170 millionths, but it started to fade lar prominence was on the NW limb at about 14 observers reported a filament MDF of
the following day and dissolved mid-disc 60,000km in height. The following day, another 3.67 and 12 reported a plage MDF of 1.88
around Nov 13. column prominence reached about 90,000km on for November.
the NE limb. Plage was reported with ARs 2887, 2891,
AR2896 S17°/331° rounded the SE limb on Of particular note on Nov 3 were ‘floating’ 2893, 2894, 2895, 2896, 2897, 2898 & 2900.
Nov 15 as a single Hsx-type sunspot. The prominences above the northern and southern Two filaments were associated with AR2891
group reached a maximum area of 80 mil- limbs, the northern object being an isolated slab on Nov 3, whilst one north–south aligned fila-
lionths but slowly decayed as it crossed the of hydrogen parallel to the limb while the south- ment was seen to bisect the group the follow-
disc, being type Hrx on Nov 21 and Axx on ern one comprised of small blobs associated ing day. This filament was still present on Nov 5
Nov 23, when in the SW quadrant. The group with other prominences on the limb. and it was estimated to be around 180,000km
was not seen on Nov 25. A pyramid-type prominence was on the SW in length.
limb on Nov 4 and a fine post-flare loop was Nothing significant was reported until
AR2897 N16°/317° appeared over the NE limb recorded on the same limb the following day. Nov 19, when a series of interesting dark fila-
on Nov 15 and was an Hsx-type sunspot on On Nov 7, an arch prominence was seen on ments were on show. These were in the NE
Nov 16, with an area of 60 millionths. This the NE limb with a flame-type prominence on quadrant but especially near the SE limb, where
group turned out to be almost a mirror im- the opposite limb. a snake-like filament winded itself between the
age of AR2896 traversing the northern hemi- opposing polarities of weak magnetic regions
sphere. The group gradually reduced in size as east of AR2896. This filament became quite a
it crossed the disc, being Hsx on Nov 21 and feature over the next few days and was reported
a small Hsx group on Nov 23. The group was through to Nov 28, becoming strong and well
Axx on Nov 24 and was not seen on Nov 25. defined on Nov 23 in particular. As the filament
neared the SW limb on Nov 27, it was estimated
AR2898 S23°/240° was over the SE limb on at about 140,000km in length.
Nov 23 and was type Bxo, consisting of two
faint sunspots. The group rapidly developed
and was type Dac by Nov 25, with an area CaK
of 160 millionths. It retained its D-class
status on Nov 26 but had declined to a Cai Most CaK plage throughout the month was
group by Nov 27, when it was mid-disc. The associated with sunspot groups. AR2896
group continued to reduce, losing its follow- was notable as it showed no CaK plage until
ing sunspots, and was type Hsx by the end of Nov 22 & 23, which is quite exceptional in the
the month. experience of the observer.
CaK MDF = 2.13 (1 observer, 15 days).
AR2899 S21°/306° formed near to the SW limb
on Nov 27, type Axx, and rotated around the
limb on the following day. Flares
AR2900 S25°/254° formed on the disc on Flares were reported by Derek Glover on
Nov 26, some 15° to the west of AR2898. The Nov 25, in association with AR2898; Monty
group was type Dac by the following day and Leventhal on Nov 1 & 5 (type 2B & 3N, respec-
was type Dao on Nov 29, with an area of 260 tively); Ken Medway on Nov 26 (type Sb) in
millionths. It remained D-class on Nov 30, A filament, imaged in H-alpha on 2021 Nov 22. association with AR2900; and Anthony Stone
with four sunspots counted. (Gary Palmer) on Nov 25 & 28.

20 J. Br. Astron. Assoc. 132, 1, 2022
Notes & News

Equipment & Techniques Section

Equatorial platforms, Part I
Martin Lewis At its simplest, an equatorial plat-
Equipment adviser form that is properly made and polar-
aligned will provide a low profile and

T his is the first of three ar- stable table, allowing anything placed Figure 1. The equatorial platform as a chopped-off cone, with the
ticles about equatorial on it to follow the rotation of the heav- axis pointing at the celestial pole.
platforms, attempting to de- ens for a limited period – typically 60
mystify these odd-looking mounts and extend minutes. In the middle of the tracking period, much better at lower altitudes and was able to
their popularity amongst imagers and observ- the table will be horizontal, but at the begin- take higher loads, but at higher altitudes the roll-
ers. Such mounts are particularly appealing to ning and end it will be tipped up by several de- ers became more vertical and forces became un-
owners of undriven altazimuth telescopes such grees. A reasonable limit on the tracking period favourable again. A variant of the Gee uses ad-
as Dobsonian reflectors; they allow the user to prevents anything sitting on the platform from ditional rollers bearing against the inside face of
have the best of both worlds – smooth manual over-balancing. the north disc, to efficiently cope with the load
location of objects based on a human up/down An equatorial platform enables you to do considerations at higher altitudes. This variant is
and left/right movement frame, combined with short-exposure imaging at high magnification really a mix of Gee and Poncet. A beautifully de-
equatorial tracking and no field rotation once the (such as for planetary, lunar and solar photogra- signed modern commercial interpretation of this
object is found. phy), lower-power visual observing over much design can be seen at
This first article will concentrate on the prin- longer periods, and deep-sky imaging at low The Gee design is conceptually simple, with
ciples of equatorial platforms and look at the power with exposures of a few seconds. You can short sections of the circular north disc driven
three main designs. The second part will look in even place a tripod on the platform, to provide from the rim. There is enough rim to allow for
detail at variants suited for heavier telescopes, tracking for wide-angle DSLR exposures of the an hour or so of driving; the rest of the full disc
whilst the third will look at drive systems and skies lasting a few minutes. is dispensed with. There can be one sector span-
platform alignment. Hopefully I will inspire a Unlike standard equatorial mounts for tele- ning the rollers, or two shorter sectors each rep-
reader or two to have a go at building a plat- scopes, the polar axis on a modern equatorial resenting about 15 to 20° of the full circle.
form themselves. platform is virtual and mostly lies outside of the To get away from the mechanical issues at
physical parts of the mount. It is this as- high or low latitudes and to maximise the plat-
pect of the design that makes them hard form stability, Georges d’Autume suggested in
(a) to fully understand. 1988 making the two north roller bearings hori-
To best visualise the essence of the zontal (Figure 2c). This supports the moveable
design, imagine a large cone placed on part of the platform in a much more mechani-
the ground, with the axis pointing at the cally favourable manner. Another advantage of
celestial pole. Imagine too that it is ar- this arrangement is that it maximises the friction
ranged to rotate about its conical axis between the roller and the edge of the drive sec-
once every 24hrs. If the cone is cut off tor, meaning it can be driven more easily by fric-
several inches above the ground and tional contact from one of the rollers. As well
the dish-shape filled in, you then have a as making the rollers horizontal, d’Autume did
flat platform which will allow anything away with the pivot at the south end and used a
placed on it to track the rotating sky circular sector at this end too. The advantage of
(b) (Figure 1, above). this is that it allows one to elevate the polar axis
Several designs of equatorial platform above the platform. One can then arrange things
exist; the differences mainly arise from so that the telescope’s centre of gravity is on the
the various methods of mechanical con- polar axis, reducing the torque on the rollers and
straint used to keep the axis pointing at minimising the likelihood of slippage if driven
the pole. from one of those rollers.
Adrien Poncet conceived the first The d’Autume platform is conceptually more
equatorial platform in 1977. The Poncet complex than the Gee, and harder to fabricate.
mount used a real pivot at the apex of This is because having horizontal rollers re-
the cone at the south end, and sliding or quires the edge faces of the sectors to be conical
rolling contacts against the inside face in form, rather than cylindrical as they are for
of the disc at the north end (Figure 2a). the Gee.
(c) It was simple to make and the north end The mechanically strongest design of all is
did not even need to be circular – just a a variant on the basic d’Autume: the so-called
plane perpendicular to the polar axis. The VNS (vertical north sector) type. This again has
mount was however only really suitable horizontal rollers, but the sectors at the north
for low loads at high latitudes. At low end, instead of being inclined, are vertically set
latitudes, the forces were unfavourable as – again with their contact faces being conical
the north disc really needed edge support instead of cylindrical. You can see superb com-
to stop the polar axis drooping. mercial platforms based on the VNS design at
Alan Gee designed a variant with the
north end explicitly circular and roll- Part II of this article will further discuss vari-
ers supporting the disc edge – these in- ants based on the Gee, d’Autume and VNS,
clined rollers were aligned parallel with comparing three modern designs suitable for
Figure 2. Schematic diagrams of (a) a basic Poncet plaftorm; the polar axis instead of perpendicular to construction by amateurs and able to support
(b) a basic Gee platform; (c) a d’Autume platform. it (Figure 2b). The Gee design worked larger telescopes.

J. Br. Astron. Assoc. 132, 1, 2022 21
Notes & News


John Chuter featured in the Decem-
Archivist ber piece. This was in
the 1997 February is-

O n p.57 is a letter from John
Cook in relation to the paper
by Mike Maunder mentioned in my ‘From the
sue. It resonates with
me as our eldest son
lives in Finland, and
Journal archive’ piece in the 2021 December having been there sev-
issue [131(6), p.349]. Letters, or Correspon- eral times in the win-
dence as they were formerly called, have ter, we know how true
been a feature of the Journal from early on. so much of this is. I
The 1897 February issue has, amongst sev- am sure it will reso-
eral other interesting ones, a lovely descrip- nate with many read-
tion (top right) of the aurora borealis from ers as well. My article
the Malverns, by Alfred Watson. It must have has come full circle,
been spectacular further north on that night. so to speak!
I have mentioned
Roland L. T. Clarkson
before, as we have his
notebooks in our ar-
chives. Shown here
(above) is the first
paragraph of a letter
written by Clarkson on
‘Terrestrial magnetism’
from the 1922 February
In the 1972 February
issue, we have a short
letter (right) by Cicely
Botley, in reference to
noises that may be as-
sociated with thunder-
storms and meteors.
For further interesting
detail, the letter trail can
be traced back through
the relevant issues that
are available in the
Journal archive on the
BAA website.
Finally, I show here a
letter by David Frydman
(bottom right), in re-
sponse to the paper by
Mike Maunder that I

22 J. Br. Astron. Assoc. 132, 1, 2022
Multiwavelength observation of
polar faculae
C. Alexandra Hart, Matt Penn & Peter Meadows

By observing the polar regions of the Sun on three occasions and in three wavebands, polar faculae in the
photosphere were studied and compared to features found in the chromosphere at wavelengths of calcium II K
and hydrogen-alpha. It was found that the white-light polar faculae are closely associated with calcium II K
bright plage, but more tenuously associated with hydrogen-alpha plage. Associations were more consistent for
hydrogen-alpha mottles, although non-specific correlations could not be excluded.

Introduction The magnetogram in Figure 1 (overleaf), acquired on 2020
Mar 25 from the Solar Dynamics Observatory (SDO) Helioseis-
Polar Faculae mic & Magnetic Imager (HMI) instrument, shows the magnetic
field lines and where they meet the polar surface (magnetic flux
‘Facula’ (singular) means ‘bright point’ or ‘little torch’ in Latin. tube footpoints). Some polar faculae of interest are circled and
In reality, these features of the solar surface (photosphere) as seen show co-localisation with these magnetic field footpoints.
in white light (WL) tend to take the form of vein-like structures Faculae can be precursors to sunspots (in the zone 0–45° in
when observed near the limb of the Sun. They are caused by latitude) and even after the sunspot has decayed, the bright facu-
changes in the solar magnetic field. The Sun generates this field lae can last for several rotations in total. However, polar faculae
internally through the motion of electrically charged gases (plas- are different to those in the sunspot zone. Found at their lowest
ma). This field is similar to that of a bar magnet, with a north and latitude during solar minimum (60°), but on average at around
south pole. The magnetic field lines are fairly uniform at the poles 70–90° latitude, these small granular or elongated flakes can last
but get stretched, pulled and amplified near the equator due to from minutes to 1–2 days at the very most, making them more
those latitudes’ faster rotation compared to the poles. Depending difficult to observe and study.4 Cortesi (1978) states that the aver-
on the particular solar cycle, the magnetic field lines are directed age lifetime of polar faculae depends upon their size and mag-
outwards from the north pole and inwards at the south pole; this netic field strength in gauss (Gs).5 Small faculae last 16 minutes
is then reversed in the next solar cycle as the Sun’s polarity flips or less (150–250Gs), medium for 39 minutes and large for 143
every 11 years.1 minutes or more, while large facular knots may last for 13 hours
Magnetic fields make their presence known on the solar sur- (900Gs).5,6 According to Müller (1954) and Waldmeier (1955),
face by changing the gas dynamics and thereby developing ei- some polar faculae have lifetimes of many days.7–9 Some fluc-
ther faculae or dark sunspots. The latter are the result of a strong tuate, some disappear, and some reappear again in a few hours.
magnetic flux stifling convection from below the photosphere, Long-lived polar faculae are always bright (more likely to be ob-
across a large area of the solar surface. The magnetic field low- served by an amateur astronomer), but the converse does not fol-
ers the gas pressure and makes the sunspot more transparent than low; bright ones are not always long-lived.10
the surrounding photosphere. This can be seen when the sunspot Together with the transitory nature of polar faculae making ob-
nears the solar limb as the ‘Wilson effect’, where an apparent deep servations challenging, the tilt of the Sun relative to the Earth can
depression or cavity-like appearance is observed. While viewing also add difficulty. Observations of the solar poles from Earth are
the evacuated magnetic regions of a sunspot, the observer can best in February/March, when the south pole is more inclined to-
see a little deeper into the photosphere, giving the illusion of wards us, and in August/September, when the north pole is tilted
a depression. towards us (Figure 2, p.25).
Faculae however are the result of smaller (and perhaps weaker) In addition, polar faculae are more frequent at solar minimum
magnetic regions on the solar surface, which do not inhibit con- and at the sunspot cycle’s rising phase; they generally disappear
vection over a large area. In faculae, as in sunspots, the magnetic from view around the time of sunspot maximum (Figure 3, p.25).12
field produces an extra pressure term which reduces the gas den-
sity and allows the observer to see deeper into the Sun. Unlike
sunspots, the faculae do not suppress convective flows, so the Chromospheric features
observer sees deeper where the granulation pattern is hotter and
brighter. When viewed near the limb of the Sun, the bright walls Very little is known as to the relationship between polar facu-
of the solar granulation are seen at a larger depth into the photo- lae as observed in the photosphere and features observed in the
sphere than the surrounding area.2,3 The scattered light from this chromosphere of the Sun. The chromosphere is traditionally de-
leakage causes the faculae to be brighter and around a few hun- fined as a layer 2,000km thick, at a height of around 500km above
dred degrees warmer than the surrounding photosphere.4 the photosphere.
J. Br. Astron. Assoc. 132, 1, 2022 23
Hart, Penn & Meadows: Multiwavelength observation of polar faculae

Figure 1. Helioseismic & Magnetic Imager (HMI) continuum image (top left) and magnetogram (top right) from the Solar Dynamics Observatory (SDO) on 2020 Mar 25.
Polar faculae of interest are circled in red (bottom left) and the continuum image was overlaid in Adobe Photoshop CS5 onto the magnetogram image (bottom right). This
highlights the co-localisation of the polar faculae with the magnetic field footpoints where they meet the polar surface.

Photospheric faculae at the poles and elsewhere on the Sun cor- on how broad the bandpass of the H-alpha filter used is, and at
respond to magnetic field footpoints (flux tube footpoints). These what precise wavelength in the line profile the observer is look-
appear bright, as previously discussed, since they allow us to see ing. In the red and blue wings of H-alpha, the evacuated magnetic
slightly deeper into the Sun where it is hotter, and thus brighter flux tube can be seen (similar to WL), allowing observation deep-
(similar to the Wilson effect observed when a sunspot is seen near er into the chromosphere or into the high photosphere and causing
the limb). a bright appearance. However, at the line core the sides of mottles
Calcium II K (CaK) emission (lower chromosphere) comes can be observed instead and so the feature may appear darker.
from shock heating of the chromosphere as waves are channelled Figure 4 (p.26) shows the same region of the solar limb in
along the magnetic field lines. In the polar regions, the magnetic H-alpha, in both the blue wing on the left and centre-line (line
field is unipolar, and it does not usually reconnect with the solar core) on the right. The area enlarged is highlighted by a box in the
surface. The wave motion is simple (radially upwards) and so the main image. In the blue wing, we can see the mottles following the
shock heating (and energy deposition) likely always corresponds magnetic flux tubes (as seen also in Figure 5) which are dark (la-
to the same location as the photospheric bright points (magnetic belled ‘a’), and the flux tube footpoint, which is bright white (‘b’).
flux tube footpoint). Thus, there is a close relationship between At the line core, these mottles also appear dark (‘a’), but the mag-
the photospheric features and those observed in the lower chro- netic footpoint is much more difficult to observe. At centre-line
mosphere (CaK).13 This has been a widely-held view since the the bright areas are more commonly termed ‘plage’ (‘c’).
1950s–’70s, when many studies were published indicating that The most common small-scale features residing in the network
WL faculae and plage as seen in the chromosphere correlate very boundaries in H-alpha are mottles. Mottles are thin jet-like fea-
closely in shape and position; they probably represent the same tures of short duration (10–15 minutes), called spicules if seen at
structures but at different heights in the solar atmosphere.14 the solar limb. These fast-moving, up-and-down flows of plasma
In hydrogen-alpha (H-alpha; mid-chromosphere), this be- (about 300km in diameter) follow the magnetic flux tubes and
comes more complicated. What is observed dramatically depends can be seen as rosettes or bushes. They rise at a rate of 20km/s (or

24 J. Br. Astron. Assoc. 132, 1, 2022
Hart, Penn & Meadows: Multiwavelength observation of polar faculae
72,000km/h) and can reach several thou-
sand kilometres in height before collaps-
ing and fading away. A short animation of
the solar limb by one of the authors (CAH)
shows the rising and falling of these mot-
tles on the surface and spicules on the limb,
during a period of 37 minutes.15
Previously, work has shown that there
is a relationship between dark elongat-
ed mottles emanating from the network
boundaries, and the photospheric bright
points. However, it is extremely difficult to
directly associate bright points to specific
dark mottles. Suematsu et al. (1995) were
able to connect a bright point and mottle
throughout its whole life,16 but they found
many mottles which were not associated
with bright points. However, some bright Figure 2. Schematic diagram of the tilt and orientation of the Sun relative to our view from Earth in spring and
points appeared at the footpoints of mottles autumn. In the northern hemisphere spring, the south polar region offers more favourable viewing, while in au-
only during their peak extension or falling tumn the north polar region does. (Courtesy of Tilting Sun software,11 © Les Cowley)
phase, rather than at the beginning (due
to compression of the atmosphere by in-
falling spicule material that penetrates deeper in the solar atmo-
sphere, thereby delivering its potential energy).16,17
Figure 5 (p.26) shows a simple diagram of the possible asso-
ciations between features of the photosphere and chromosphere.
The bright points of the magnetic flux tubes, detected as faculae
in the photosphere, follow through to bright points/plage in the
CaK wavelength (lower chromosphere), through to either mottles
or bright plage in the H-alpha wavelength (mid-chromosphere).

Polar faculae were observed on three days with clear skies: 2020
Feb 8 (morning), Feb 22 (afternoon) and Mar 25 (morning). On
Mar 25, the seeing conditions were good enough to support a Tele
Vue ×3 Barlow lens; for the other two observing sessions the see-
ing only supported use of a Celestron ×2 Barlow.
All observations were made using a TEC 140 refractor stopped
down to 100mm aperture and a ZWO ASI 174M camera, except Figure 3. Plot showing the BAA mean daily frequency (MDF) of polar faculae
over the last solar cycle and a half. The frequency for the north polar region is
for Feb 8 when a FLIR Grasshopper 3 (ICX674) camera was used. shown in black, and that for the south polar region in red. There is a clear inverse
Imaging started for each session with WL (photosphere), using correlation with sunspot activity, where the number of polar faculae is greatest
a Baader photographic Herschel wedge with a continuum filter. during periods of low sunspot activity in solar minimum and lowest during solar
maximum (the Cycle 24 maximum was in 2012–’14).12
First, a whole-disc image was taken, making sure that the camera
was correctly aligned. With the aid of Tilting Sun software,11 the
north or south polar region could be identified before continuing Changing filter sets and imaging runs took between 10 and 30
by taking ×2 or ×3-magnification images of the poles. minutes, so each imaging session (with all three wavelengths)
Next, the Herschel wedge was removed and a Lunt CaK 1800 ranged on average between 55 and 82 minutes in total (well
wedge was placed in the telescope to allow for CaK observations within the 143 minutes for large polar faculae as described by
(lower chromosphere). Again, the full disc was initially imaged Cortesi et al.).5
to establish the polar region, followed by ×2 or ×3-magnification Once all the images were acquired, they were first stacked in
images. AutoStakkert! 3.18 The best 5% from 1,000 images were used
Finally, the filters were changed to a Solarscope DSF 100 filter in the final stack. The stacked images were then sharpened in
set (0.5Å) to observe the H-alpha centre-line (mid-chromosphere). ImPPG,19 and transferred to Adobe Photoshop CS5 for final his-
Following the same order as before, a full-disc image was initially togram curves as well as brightness and contrast enhancements.
taken followed by the ×2 or ×3-magnification images. Images from all three wavelengths were overlaid using the Lay-
As all the observations were made on the same telescope, po- ers tool in Photoshop and the polar faculae aligned between
lar faculae were not imaged at the same time in all wavelengths. the images.

J. Br. Astron. Assoc. 132, 1, 2022 25
Hart, Penn & Meadows: Multiwavelength observation of polar faculae

Figure 4. The same area of the solar limb was imaged on 2015 Aug 8 in the blue wing (left) and centre-line (right) of H-alpha. The enlarged region (bottom images) is
highlighted by a square in the main images. In the blue wing, the black mottles (also known as spicule bushes) are highlighted in the sketch and labelled as (a). In the blue
wing the magnetic field and mottle footpoints are bright white (labelled as (b)) and more easily observed compared to the centre-line image, where these footpoints are
more obscured by the mottles. The bright areas in the centre-line are more commonly termed ‘plage’ (labelled as (c)).

On 2020 Feb 8, from 10:54 to 11:49 UTC (55 minutes
between WL and H-alpha observations), the north po-
lar region was observed in detail. Eleven bright polar
faculae regions can be seen in the northern polar im-
age of Figure 6a and seven, shown in Figure 6b, were
studied in more detail. For region A, three bright points
can be identified; both the WL and CaK at 393.4nm
correspond and show a similar bright appearance. In
H-alpha at the 656.3nm centre-line, the upper bright
point corresponds with an area of bright plage in that
waveband, whereas the mid and lower bright points
correspond with a mottle/spicule bush. For region B,
the WL and CaK again have a very close association
between their features, but in H-alpha the bright area
to the right is associated with bright plage and mottles
emanating from this region. In region C, the WL view
is less clear due to the position being away from the
solar limb,20 but in CaK the bright plage is apparent Figure 5. Sketch of possible associations between the features observed in white-light (photo-
and matches that of the WL (right arrow). Again, in sphere) and the wavelengths of calcium II K and H-alpha. Bright magnetic-field-line footpoints
are seen in both the photosphere and lower chromosphere of CaK as well as the wings of H-alpha.
H-alpha, mottles can be seen rising up from the bright In the centre-line of H-alpha (middle to upper part of the chromosphere), dark mottles/spicules are
plage. In region D, both WL and CaK correspond, observed following these field lines.

26 J. Br. Astron. Assoc. 132, 1, 2022
Hart, Penn & Meadows: Multiwavelength observation of polar faculae


Figure 6. (a) North polar faculae on 2020 Feb 8 at 10:54–11:49 UTC, imaged using a TEC 140, ×2 Barlow, Grasshopper 3, Baader Herschel wedge and continuum filter.
The seven bright faculae points highlighted by arrows were studied in more detail in three different wavebands. (b) A comparison of polar faculae regions A to D, in three
wavebands: white-light (Baader Herschel wedge and continuum filter), CaK (Lunt CaK B1800 wedge) and H-alpha (Solarscope DSF 100). Taken 10:54–11:49 UTC.
Arrows indicate highlighted polar faculae.

while in H-alpha two mottles can be seen coming from the area of (b)
bright plage at that point.
On 2020 Mar 22, between 14:06–15:18 UTC (72 minutes
between WL and H-alpha observations), the south polar region
was observed at ×2 magnification. Figure 7a (overleaf) shows a
comparison between the SDO/HMI image and the WL, CaK and
H-alpha images taken during this session, with the red bar indi-
cating the south pole. A total of 11 polar faculae are marked in
Figure 7a and nine (shown in Figure 7b) were observed in closer
detail. In regions A–C, all the WL bright points and CaK plage
co-localise together. In H-alpha, the details are more subtle due
to poor seeing, but in most cases, mottles can be seen coming
from these regions.
On 2020 Mar 25, between 08:56–10:18 UTC (82 minutes be-
tween WL and H-alpha observations), seeing conditions were
more favourable and ×3 magnification was used to study the south
polar region. Five areas were investigated, containing eight bright
faculae for study, as shown in Figure 8a (p.29). In Figure 8b, again
the polar faculae in WL and bright plage in CaK show a very close
association, with all bright areas in a similar position. In H-alpha
the correlation was more tenuous; all the bright CaK plage cor-
responded to a similar general area of associated bright H-alpha
plage (footpoints), but all had mottle/spicule bushes emerging
from these regions in various directions, making the exact loca-
tions of the polar faculae more difficult to discern.

study by Narang et al. (2019), who found that the calcium II H
Interpretation (396.9nm) polar network bright points are associated with pho-
tospheric magnetic patches underneath.13 However, the Ca II H
From these results, it is clear that WL faculae seen at the polar line reveals structures in the lower chromosphere and interpolat-
regions do correspond well to the small areas of plage found in ing these results into the mid-chromospheric region of H-alpha
the lower chromosphere in CaK. This is similar to findings in a is more difficult. The observations in this study were taken over

J. Br. Astron. Assoc. 132, 1, 2022 27
Hart, Penn & Meadows: Multiwavelength observation of polar faculae

Figure 7.
(a) – Above: SDO/HMI continuum image (top left) taken at a similar time to a period of 55–82 minutes, due to the necessity of filter changes
the white-light image (bottom left) and showing a high degree of similarity between WL, CaK and H-alpha images. Therefore, only observa-
between the positions of the polar faculae marked by arrows. Positions of tions of medium-sized or larger, and more stable polar faculae and
these faculae are also shown in the calcium II K (top right) and H-alpha (bot-
tom right) images. Taken on 2020 Mar 22, 14:06–15:18 UTC. their associated chromospheric features could be studied, rather
than the smaller and more transient ones.
(b) – Below: A comparison of polar faculae regions A, B and C in three
wavebands: white-light (Baader Herschel wedge and continuum filter), CaK As discussed previously, mottles can rise and fall over a pe-
(Lunt CaK B1800 wedge) and H-alpha (Solarscope DSF 100). Taken on riod of 10 minutes and so the areas studied here are intrinsically
2020 Mar 22 at 14:06–15:18 UTC. Arrows indicate highlighted polar faculae orientated to include more stable polar faculae and mottle foot-
and the red bar indicates the position of the south pole.
points. To overcome the issue of feature evolution, studies like
these should ideally be carried out synchronously in all three
wavebands if possible, because of the quick-changing nature of
the solar surface. In this research, it would have been helpful to
include a further WL or blue-wing H-alpha observation at the end
of each session to track changes in the polar faculae during the
duration of the study.
In the literature, very few studies have looked at the associa-
tion between bright points in WL, CaK and H-alpha; only one
has successfully managed to follow a mottle from a bright point
throughout its life.16 Another study used the bright structures in
the blue wings of H-alpha as a means of locating polar faculae
more easily in WL, although even they state that sometimes the
H-alpha brightenings are hidden due to the complex structures
(mottles) present in the chromosphere.20
This study was made more difficult by the area being anal-
ysed. The polar regions being close to the solar limb favours easy
observation of polar faculae in WL, but makes detecting these
features in CaK and H-alpha more challenging due to observing
mottles from the side (line-of-sight effect) at this angle. These ob-
scure the view downwards to the bright footpoints below. Previ-
ously, when observing an emerging flux region at the apparent
centre of the solar disc in a study from 2010,21 it was easier to
28 J. Br. Astron. Assoc. 132, 1, 2022
Hart, Penn & Meadows: Multiwavelength observation of polar faculae

Figure 8.
(a) – Above: SDO/HMI continuum image (top left) taken at a similar time to the
white-light image (top right), showing a high degree of similarity between the posi-
tions of the polar faculae marked by arrows. The positions are also shown in the cal-
cium II K (bottom right) and H-alpha (bottom left) images. Taken on 2020 Mar 25,
08:56–10:18 UTC.
(b) – Right: A comparison of polar faculae regions A, B, C, D and E, in three
wavebands: white-light (Baader Herschel wedge and continuum filter), CaK (Lunt
CaK B1800 wedge) and H-alpha (Solarscope DSF 100). Taken on 2020 Mar 25,
08:56–10:18 UTC. Arrows indicate highlighted polar faculae and the red bar indi-
cates the position of the south pole.

look directly downwards relative to the solar surface and com-
pare the features in CaK and H-alpha lines. This study was also
completed in near-synchronous time due to both Coronado PST
telescopes being mounted side-by-side. The area was imaged di-
rectly, in one waveband after the other, with the only delay being
the time taken to swap the camera between the two. The images
were overlaid and gradually merged, starting with the view of the
CaK bright plage area and progressing through to the H-alpha
image. This slowly revealed the positions of arch filaments
in H-alpha and where they were situated in respect to the CaK
view. Arch filaments are similar to mottles, except they are much
larger, associated with stronger magnetic flux tubes that recon-
nect with the solar surface in a loop. The arch-filament footpoints
were indeed associated and matched the size and position of the
bright plage spots in CaK.21 This study was slightly different
due to it being of higher-magnetic-flux features compared to the
lower-magnetic-activity regions of polar faculae, but they were
easier to see and study.
Despite the limitations of both these studies, it is pos-
sible to conclude that observations in CaK and H-alpha do as-
sociate with the same features and that bright plage in CaK
J. Br. Astron. Assoc. 132, 1, 2022 29
Hart, Penn & Meadows: Multiwavelength observation of polar faculae
corresponds with bright plage in H-alpha and the footpoints of 3 Keller C. U. et al., ‘On the origin of solar faculae’, Astrophys. J., 607,
1.59–1.62 (2004)
mottles / spicule bushes. 4 Jenkins J. L., Observing the Sun – A pocket field guide, Springer, New York,
2013 [DOI 10.1007/978-1-4614-8015-0]
5 Cortesi S., ‘Facules polaires’, Astron. Mitt. Eidgen. Sternw. Zurich, 362(1)
Summary (1978)
6 Solov’ev A. A. & Kirichek E. A., ‘Structure of solar faculae’, Mon. Not. R.
Astron. Soc., 482, 5290–5301 (2019)
From this study, we can conclude that polar faculae as a 7 Muller R., Zeitschr. F. Astrophys., 35, 61 (1954)
8 Waldmeier M., ‘Polar fackeln’, Zeitschr. F. Astrophys., 38, 37 (1955)
white-light feature of magnetic field lines are closely associated 9 Makarov V. I. & Makarova V. V., ‘Polar faculae and sunspot cycles’, Sol.
with areas of bright plage in the calcium II K line. It is possi- Phys., 163, 267–289 (1996)
ble that these regions also associate and co-localise with mottle 10 Bispham K. & Hill H., ‘Observations of polar faculae’, J. Brit. Astron. Assoc.,
79(3), 200–212 (1969)
footpoints / spicule bushes in the H-alpha centre-line wavelength. 11 Cowley L., Tilting Sun software:
This is an exciting area of study for amateur solar astronomers in 12 Meadows P., ‘Polar faculae observer’s challenge’:
the future. It presents a significant challenge to study in all three node/17279
13 Narang N. et al., ‘Association of calcium network bright points with under-
wavelengths synchronously in high resolution, but the rewards neath photospheric magnetic patches’, Sol. Phys., 294, 1–10 (2019): https://
would be to follow a particular region in greater detail over a lon-
ger period of time and perhaps watch the evolution of a mottle. 14 Bray R. J., ‘High-resolution photography of the solar chromosphere’, Sol.
Phys., 4, 318–322 (1968)
15 An animation from 2016 May 29 at 09:09–09:46 UTC, showing fast-rising and
falling spicules/mottles on the solar surface and limb in the H-alpha centre-line,
Acknowledgments can be seen at:
16 Suematsu Y., Wang H. & Zirin H., ‘High-resolution observation of disk
The Solar Dynamics Observatory (SDO) Helioseismic & Mag- spicules: I. Evolution and kinematics of spicules in the enhanced network’,
netic Imager (HMI) continuum images are courtesy of NASA/ Astrophys. J., 450, 411 (1995)
17 Tsiropoula G. et al., ‘Solar fine-scale structures: I. Spicules and other
SDO and the HMI science team. small-scale, jet-like events at the chromospheric level: observations and
Address (CAH): British Astronomical Association, Burlington House, Piccadilly, physical parameters’, Space Sci. Rev., 169, 181–244 (2012) [DOI 10.1007/
London W1J 0DU [] s11214-012-9920-2]
18 Kraaikamp E., AutoStakkert! 3 software:
19 Szczerek F., ImPPG software:
20 Blanco Rodriguez J. et al., ‘Study of polar faculae with north pole coverage of
References & notes the Sun’, Modern Solar Facilities – Advanced Solar Science, 181–184 (2007)
21 Hart A., ‘Observing the Sun in Ca II K’:
1 Wilkinson J., New Eyes on the Sun – A guide to satellite images and amateur solarastrophotography/Observing%20in%20Ca%20II%20K.pdf
observation, Springer-Verlag, Berlin/Heidelberg, 2012
2 Spruit H. C., ‘Pressure equilibrium and energy balance of small photospheric
fluxtubes’, Sol. Phys., 50, 269–295 (1976) Received 2020 August 6; accepted 2020 October 28

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30 J. Br. Astron. Assoc. 132, 1, 2022
Jupiter in 1949 & the Revival of the
South Equatorial Belt
Richard McKim The 36th report of the Jupiter Section. Director: J. H. Rogers.

Until now there has never been a comprehensive account of Jupiter’s 1949 apparition, in which there was a Revival
of the South Equatorial Belt (SEB). On opposition day, Jul 19, despite the SEB south component not having faded to
invisibility, the first white spot of the Revival was seen. The spot had originated within a pre-existing SEB(S) dark ‘barge’,
close to the longitude of E. J. Reese’s ‘Source B’. The Revival led to a fading of the initially conspicuous Great Red Spot
(GRS), and the development of the Red Spot Hollow (RSH). The S. branch of the Revival was weak, with small retro-
grading dark spots which failed to pass the GRS, although their velocity was typical. The N. branch was also less active,
with some prograding dark spots passing only slightly beyond the GRS/RSH, which also exhibited a typical drift. On
the other hand, the central branch was unusually active, with a succession of long-lived white spots and dark columns
(mean drift rate Δλ2 = –67°/30 days). The p. end of the Disturbance in the SEB Zone faded before reaching the RSH. In
addition to darkening the SEB, the Disturbance gave rise to slowly-prograding dusky columns in the S. Tropical Zone.
Other features were the continuing presence of the S. Temperate white ovals, a very active Equatorial Current, dark
spots at the N. edge of the North Equatorial Belt and at the S. edge of the North Temperate Belt, and a dislocated
section of N. Temperate Zone. Accurate photographic belt latitudes fill another gap in the literature. We also provide
the first colour images from 1949, by compositing filter photographs from the Lowell Observatory, Arizona. That the
vast majority of longitudes were obtained at the eyepiece reminds us of the great value of visual observation in provid-
ing the foundation of so much of our knowledge about Jupiter.

Introduction In the UK, observations were contributed to the Section by
G. E. D. Alcock, W. F. C. Blumer, J. M. A. Danby, Miss M.
At opposition on 1949 Jul 19, Jupiter had a considerable southern Davies-Scourfield, W. E. Fox (who made the largest number of
declination of –21°, though its meridian altitude had improved a domestic central meridian (CM) transit measurements), F. Perry,
little since 1948 (opposition Jun 15, declination –23°). Apart from H. Wildey and T. W. Williams.7 A small number of additional data
a short account by the discoverer of the South Equatorial Belt were gleaned from the papers of the UK observers F. J. Acfield,
(SEB) Revival,1 this important opposition was never discussed L. F. Ball and E. H. Collinson.8 Artistic drawings were made by
in BAA publications,2 while an Association of Lunar & Planetary Alcock, Ball, Collinson and Wildey.
Observers (ALPO) report published years later was based upon To supplement these data, we referred to publications by
insufficient longitude data for the Revival spots.3 Despite the ex- J. H. Focas (400mm OG, Athens Observatory),9 and to the original
ceptionally long interval it is thought by the author of this paper observations of C. F. M. du Martheray (Geneva, Switzerland),10
that a detailed account would still be useful, for the 1949 Revival both former members of the Section. We also had access to useful
had some unusual aspects that should be put on record. Further- observations by W. Löbering in Germany,11 and to many excellent
more, there are very few published Jovian belt latitudes for the unpublished photographs by Dr E. C. Slipher at Lowell Observa-
years between 1947 and 1951, and reliable data to fill the gap tory. From the latter we could prepare some colour composites.12
are available. Observations covered the period 1949 Feb 7 to Dec 20. Most of
The low altitude of Jupiter in 1949 dictated that the best ob- the colour estimates were made by Haas, Löbering, du Martheray,
servations would be made from outside the UK. The majority of McIntosh and Reese, and intensity estimates by Reese: see Table 1.
longitude measurements were obtained from central meridian Belt latitudes were measured from the best photographs (Table 2).
transits, and the bulk of these were made by three American BAA This report is a sequel to that for 1948,13 which was published
members using comparatively small reflectors: W. H. Haas (Albu- soon after the opposition. At that epoch the BAA reports were
querque, New Mexico), E. E. Hare (Owensboro, Kentucky) and numbered chronologically, and this is therefore the 36th report of
E. J. Reese (Uniontown, Pennsylvania). Reese had just been ap- the Section.
pointed as the ALPO’s first Jupiter Recorder and obtained 1,570
timings. Scans of Haas’ and Reese’s notebooks (archived in New
Mexico State University Library) have enabled access to all of The observations
their detailed notes.4 An equally valuable set of observations was
made with a large aperture by the discoverer of the 1949 SEB Colour and intensity estimates are summarised in Table 1. Table 2
Revival, R. A. McIntosh (Auckland, New Zealand),1 while other presents belt latitudes, while tables of drift rates and rotation peri-
good southern hemisphere work was carried out by F. M. Bateson ods follow the general text. To conform to the style of Jupiter re-
(Rarotonga, Cook Islands). Taking advantage of his low latitude, ports from that era, longitudes of features in Systems I and II are
S. Murayama (Tokyo, Japan) also made a long series of draw- indicated by λ1 and λ2, respectively, while Δλ1 and Δλ2 denote drift
ings and transits.5 Some observations were also contributed by rates in degrees per 30 days (hereafter °/mo). CM1 and CM2 denote
G. Ruggieri (Venezia, Italy).6 the longitudes of the central meridian according to Systems I and II.
J. Br. Astron. Assoc. 132, 1, 2022 31
McKim: Jupiter in 1949 & the Revival of the South Equatorial Belt

North Polar Region (NPR)
Visual observers could detect a North
North North Temperate Belt (NNNTB)
within the polar shading, and high-reso-
lution photographs taken at Lowell Ob-
servatory in July show at least one more
belt to the north. It was possible to estab-
lish a tentative drift rate for one dark spot
(shown in Figure 2C) in the NNN Tem-
perate Current.

North North Temperate
Zone (NNTZ)

The zone was somewhat shaded for the
most part. A small, bright white NNTZ
oval was photographed at λ2 = 343° by
Slipher on Jul 12 (Figure 1). A large
but faint white oval was photographed
at λ2 = 003° on Jul 9, while another lo-
cated at λ2 ~ 210° was photographed on
Jul 15 & 18 and Aug 16 (Figures 1 & 2B),
as well as being confirmed visually by
Murayama, Jul 16 – Aug 11 (Figure 8).
Figure 1. Previously unpublished 1949 photographs obtained by Dr E. C. Slipher with the 26-inch (60cm) OG at The latter oval interrupted the NNTB.
Lowell Observatory, Arizona, USA, in yellow (Y) or blue (B) light, or no filter. The author selected the sharpest
images from each negative and composited and enhanced them with Registax. See also Figure 2A–B. (Note: Here
and in all the other telescopic images, south is uppermost.)
North North Temperate Belt
The belt contained a number of long dark
sections that were nearly stationary in Sys-
tem II (with drifts typical of NN Temper-
ate Current A), two of which almost cer-
tainly continued into the next apparition.

North Temperate Zone
For the most part a light zone, the NTZ
was shaded within one section containing

Figure 2. 1949 observations in colour (see also
Table 1). Both (A) & (B) are photographs taken
by E. C. Slipher at Lowell Observatory (24-inch
(600mm) OG); red, yellow and blue filter images
were composited in Registax by the author, with
these colour composites prepared by Emmanuel
(A) Jul 9, 08:32 UT, CM1 = 118°, CM2 = 018°; note
the dark spots upon the SEB(S), and in (A)
and particularly (B) the orange tint to parts
of the EZ (especially the EZ(S) and SEBZ).
(B) Jul 18, 06:58 UT, CM1 = 043°, CM2 = 234°; the
GRS is at the CM.
(C) Jul 11, 05:30 UT, CM1 = 323°, CM2 = 208°:
drawing by E. J. Reese (152mm refl., ×200).
(D) Jul 25, 22:28 UT, CM1 = 276°, CM2 = 050°:
drawing by W. Löbering (265mm refl.,
×225). Io and its shadow are near the f. limb.

32 J. Br. Astron. Assoc. 132, 1, 2022
McKim: Jupiter in 1949 & the Revival of the South Equatorial Belt
a North Temperate Disturbance (or N Temperate Disloca- that moved in the N Tropical Current. A thin, elusive N Tropical
tion; NTD). Zone Band (NTropZB) was occasionally seen visually (Figure 9)
For several months the NTD existed as a sector some 70° long, or photographed by Slipher (particularly on Jul 12; see Figure 1).
within which the normal pattern of belts from the NTB to the
NNTB was interrupted. At λ2 = 102° (opposition), the NNTB – or
a southern component of it – abruptly moved southwards, wid- North Equatorial Belt (NEB)
ened and darkened to form a conspicuous NTZ Band (NTZB).
From here, the normal NNTB was either absent or faint, but it re- The NEB was broad and dark. It was not obviously double,
appeared or intensified towards the following (f.) end of the dislo- though some sectors had darker edges. Its reddish-brown colour
cation. The NTZ between the NTB and NTZB was also darkened was strikingly intense to Reese in July.
within the NTD. At λ2 = 174° (opposition), the dislocated section
was terminated by a conspicuous white oval lying between the NEB(N): This showed several projections into the NTropZ, a
NTB and NTZB (Figures 1 (Jul 15 & Aug 16), 2C, 6, 12 & 13), few being more prominent dark ‘barges’, of which No. 11
following which the NTZB exhibited a slight ‘step-down’ (less exhibited a ‘tail’ to du Martheray, June–July. There were a few
evident after early July) to unite it with the NNTB. A similar step
was observed in 1972–’75.14 Just following this longitude, the Table 1. Colour & intensity* observations, 1949
NNTB was interrupted during July–August by an NNTZ white
oval, previously mentioned under ‘NNTZ’, and following the Feature Haas du Martheray Reese
oval by means of another small step-down (Figures 8, 13 & 17) ’49 ’48
the NNTB finally regained its canonical latitude. SPR blue–grey blue–grey blue–grey 4.0 (4.1)
The f. end of the darkened section of NTB and NTZB had first SSTB brown–grey brown/red grey 3.7 (3.8)
been recorded by Reese on May 6, but a definite preceding (p.) STZ white – white 5.1 (7.3)
end did not appear till Jun 6, with the white oval at the f. end be- STB red–brown red–brown to brown 2.8 (2.9)
ing the last component to appear, on Jul 3. The dislocation and greenish
white oval, together with the p. end of a lighter section of NTZ GRS – reddish to ochre 4.8 ( – )
located outside the NTD, all moved with positive drifts typical of
RSH white – white 6.4 (6.1)
N Temperate Current A.
STropZ white – white 7.4 (6.1)
In mid-August, the white oval at the f. end of the NTD was
SEB(S) red–brown red–brown red, 2.5 (2.8)
in conjunction with a white oval that interrupted the NNTB (see changing
previous section). After then, the NTD faded, with the p. and f. to grey
ends of the dark sector infrequently recorded, and the white oval SEBZ yellowish– – ochre, 5.0 (4.8)
last observed on Sep 10. The p. end was last recorded on Oct 3; white changing to
a well-defined f. end was last seen on Aug 26, but it continued at
SEB(N) red-brown red-brown red-brown 3.0 (2.5)
the extrapolated longitudes in the form of an NTZ dusky column
EB grey grey grey-brown 3.4 (4.1)
on Sep 22 and an NNTB dark spot on Oct 19.
EZ orange- or grey ochre, 4.8 (6.9)
yellow-grey changing to
to white yellow-white
North Temperate Belt (NTB) NEB red-brown red-brown red-brown 2.5 (2.8)
NTropZ white cream white 7.3 (7.3)
This was a well-marked belt. An NTZ disturbance involving the NTB red-brown red-brown grey-brown 3.6 (3.8)
NTB was described in the previous section. NTZ white cream yellow-white 5.3 (6.2)
On Nov 11, Murayama drew four tiny well-defined dark spots NNTB† red-brown red-brown brown 3.3 (3.7)
(Figure 23) just south of the S. edge of the NTB between λ2 ~ 14 NPR blue-grey slightly brown blue-grey 4.0 (4.1)
to 68°. These looked like NTB jet-stream spots, and he confirmed
the activity on Nov 18. An earlier drawing on Nov 6 showed a *The intensity estimates are on the ALPO scale of 0 (black) to 8 (bright white),
single, less well-defined feature towards the f. limb, located at from observations on 73 nights. Bracketed values give Reese’s averages for
the previous, 1948 opposition. (The ALPO scale is in the reverse sense to the
λ2 ~ 99°. The spots did not endure, but good observations so late planetary intensity scale used by the BAA since 1946.)
in the apparition were very few: no drift rate could be inferred. In †It is assumed that Reese saw the NNTB rather than the NNNTB in 1948.13
an interim ALPO report, Reese mentioned that D. O’Toole had
also observed them.2 Other observations:
Slipher’s photographs from Jul 9 & 18, taken in R, Y & B filters and composited
There had previously been a substantial outbreak of NTBs in Figure 2, show that the SEB(N) was notably reddish (especially on Jul 18), in
jet-stream spots in 1939–’40, and sparser activity until 1943, but contrast to the dark grey or grey-brown SEB(S). There was a weak orange tint
no record in subsequent years. Rogers (2017) notes that Revivals to parts of the EZ (especially the southern part) and the SEBZ. The NEB was
dull brown, although the northern part was redder on Jul 9. The STB and NTB
of the SEB and NTB are sometimes associated in time.15 and fragmentary EB were neutral.
Focas and du Martheray found the NEBs festoons bluish to brownish, while
Reese found them blue-grey or blue-black. McIntosh found the GRS pink, July
to September. On Jul 4, Hare found the GRS dusky pink, the SEBZ bright yel-
North Tropical Zone (NTropZ) low, the EZ orange and the NEB dark brown. On Jul 25, Löbering (Figure 2D)
showed the NEB as strongly reddish-brown, the STB similarly, and the NTropZ
This was always very bright, and its S. part contained a number slightly yellowish. Ruggieri (120mm OG) saw the NEB as brownish and the
polar regions blue-green.
of white spots adjacent to or indenting the N. edge of the NEB

J. Br. Astron. Assoc. 132, 1, 2022 33
McKim: Jupiter in 1949 & the Revival of the South Equatorial Belt
well-defined and enduring white bays (as in 1948), for which
reliable drifts could also be established.

NEBZ: The NEB interior showed several rifts – as in 1948 – that
moved at a rate intermediate between Systems I and II. Two
were well-enough observed to derive good drift rates.

NEB(S): The S. edge of the belt was extremely active, with many
festoons joining the EB, and some continued to the N. edge of
the SEB in places where the Equatorial Belt (EB) was absent.
There were also numerous white spots in the EZ(N), against
the S. edge of the NEB. The festoons and EZ(N) white spots
showed similar small negative drifts in System I, and the gen-
eral appearance of the chart was one of regular motions across
all longitudes.

Equatorial Zone (EZ)

In 1949 March the EZ was of normal brightness, similar to
1948. It darkened steadily during April–June and exhibited a dis-
tinct yellow-ochre tint to Reese (and even an intense orange on
Jun 25/26), while Haas in June sometimes found it orange-grey
or yellow-grey. Reese’s drawings of May 12 and Jun 12
(Figures 4 & 5) show the zone’s unusual darkness well. From July
onwards, the zone began to lighten again (Figures 6–10). Colour
images and drawings (Figure 2) showed only weak colour, mainly
in the south, though the SEB(N) was notably orange.
IAU Circular No. 1230 stated that McIntosh had seen a distur-
bance in the EZ,16 with ‘rapid development’ on May 6. However,
the EZ was already very active then, and our records reveal noth-
ing significant about that date.

EZ(N): Crossed by numerous NEBs festoons, with many
well-marked white spots. Some of the larger festoons (in lon-
gitudes where the EB was absent) reached as far as the SEBn.

EB: This was well marked and, unusually, it was possible to
follow some darker sections over long-enough intervals to
Figure 3. Drawings of the Great Red Spot by E. J. Reese (above; 152mm refl., measure drift rates. The EB was often reinforced by NEBs
×200) and C. F. M. du Martheray (below; 135mm OG, mostly ×156 & ×196),
showing its transition to the Hollow, 1949 March–November. (Approximately to festoons, but there were also some festoons that joined it from
the same scale.) the SEBn.

Figures 4–6. Drawings from 1949 by E. J. Reese (152mm refl., ×200).
4. May 12, 08:40 UT, CM1 = 319°, CM2 =301°; the SEB(S) is still dark; several NEBZ rifts are seen.
5. Jun 12, 07:07 UT, CM1 = 120°, CM2 = 226°; conspicuous GRS, with S. Temperate white oval BC in conjunction with it.
6. Jul 3, 07:31 UT, CM1 = 213°, CM2 = 158°; the SEB Revival would develop from the small SEB(S) barge; also note the NTZ white oval.

34 J. Br. Astron. Assoc. 132, 1, 2022
McKim: Jupiter in 1949 & the Revival of the South Equatorial Belt
EZ(S): This was on average slightly darker than the N. part and Table 2. Zenographic latitudes of the belts, 1949
was crossed by the aforementioned SEBn festoons. A few
longitudes showed dark spots upon both the EB and SEB(N), Feature
Slipher photos White photo Peek
nearly in conjunction (sometimes physically connected) and (no. measures) (no. measures) micrometrical
moving together at the same drift rate, close to that of the South
Equatorial Current (SEC). The normal SEC spots moved very SSSSTBn* –66.8 (2) – (–)
SSSTBc* –56.6 (2) – (–)
slightly faster than System I. SSTBc* –43.6 (2) – (–)
STBc –30.8 (4) –33.5 (1) (–30.5)
GRSs –27.7 (1) – –
GRSn –13.8 (1) – –
South Equatorial Belt (SEB) SEB(S)s –19.5 (4) –18.4 (1) (–21.8)
SEB(S)n –15.4 (4) – (–)
The SEB prior to the Revival SEB(N)s –10.0 (4) – (–)
SEB(N)n   –7.4 (4) –4.7 (1) (–7.2)
EBc   –1.6 (4) – (–)
SEB(N): A thin, dark belt. It was largely featureless in the months NEB(S)s   +8.3 (4) +6.9 (1) (+6.8)
before opposition, with a few short-lived dark spots (some- NEB(N)n +17.5 (4) +20.8 (1) (+19.5)
NTBc +28.8 (4) +29.3 (1) (+30.3)
times with festoons projecting into the EZ(S)) moving at drifts NNTBc +37.4 (4) – (–)
close to System I. NNNTBc* +49.2 (4) – (–)
NNNNTBs* +58.0 (4) – (–)
SEBZ: This zone was strongly yellow prior to the Revival, as
it had been in 1948, and its colour intensity was striking to Notes: Four Lowell Observatory Jul 12–15 photographs (Figure 1) were mea-
sured by the author (excluding the region of the dislocation within the NTZ),
Reese on Jun 22. Slipher’s July RGB composite photographs and ALPO observer E. K. White’s September photo by Reese. B. M. Peek’s
(Figure 2A–B) show a weak orange or yellow tint, less intense 1947 data are given for comparison,37 none being available for 1948.
than that of the EZ(S). The N. and S. edges of the STZ white ovals BC and DE were at latitudes –32.0
and –36.5°, according to the author’s measures upon the Lowell photos.
SEB(S): The thin SEB(S) was still very dark, as in 1948, and *The nomenclature for these high-latitude belts may not be correct. As noted in
the text, the latitude of the belt designated ‘SSTB’ is more typical of the SSSTB.
intensely red – initially more so than the rest of the belt –
though the SEB as a whole was no longer as dark as the NEB.
Before opposition, the SEB(S) faded somewhat and became how in the 2007 and 2010 Revivals,15 the initial SEB(S) white
less reddish. Slipher’s photographs (Figure 2A & B) show the spot developed within a pre-existing cyclonic oval, or ‘barge’. As
SEB(N) orange-red but the SEB(S) nearly neutral in colour.12 the p. end of the new disturbance moved away from its source in
On Jul 27, du Martheray found the SEB preceding the Great the direction of decreasing longitude, new dark spots developed
Red Spot (GRS) to have a slightly bluish tone. (Otherwise he within the S. part of the newly darkened stretch of belt, which
described the components as red-brown.) showed only small drifts with respect to System II.
Independent discoveries of the Revival were made by Hare,
Löbering, Murayama and Reese in July, and on Aug 19 by both
Origins of the SEB Revival Bateson, and I. L. Thomsen (Carter Observatory, Wellington,
New Zealand). It was Thomsen who published an alert in the IAU
Reese found the SEB(S) less dark than the South Temperate Circulars,16 and Bateson alerted the Jupiter Section.17 With noti-
Belt (STB) on Jun 8, while on Jun 25 and Jul 1 he noted how fication arriving so late, no BAA Circular was issued.
it had faded. Unusually for an SEB Revival, it did not fade to
near-invisibility. Fox noted a dark edge to the S. border of the
belt on Jul 10, but the whole belt still appeared faint to him on The p. end & the central branch
Jul 22. From March there were a few dark barges within the S.
component, which moved with small positive drifts in System II The initial white spot rapidly expanded northwards to fill the space
(Figures 6, 7 & 9). between the SEB N. and S. components, becoming surrounded by
The 1949 SEB Revival began in typical fashion, with a small, dark matter (Figures 7 & 10). As it moved off in decreasing longi-
brilliant white spot located in the S. part of the SEBZ overlap- tude, another SEBZ white spot formed at the original source and
ping the SEB(N) N. edge. The initial spot was first observed by exhibited a similar drift to the first, to be followed in the same way
McIntosh at λ2 = 163° on Jul 19 (Figure 7).1 Murayama had ob- by further new white spots appearing at an average rate of one
served this longitude on Jul 16 and had seen nothing unusual; nor every six days, until a remarkable string of such spots existed (see
had McIntosh himself on Jul 12. The spot was photographed by Figure 15A). Subsequent white spots were seen to form in the S.
Slipher on Jul 20 at λ2 = 161°: see Figure 1. part of the SEBZ, like the initial spot, at least whenever they were
In 1949 July, three quite long-lived and slightly elongated dark caught at the point of origin. McIntosh often described the spots as
barges were already present within the SEB(S), all slowly retro- very bright, and Fox described one seen on Oct 21 as ‘glittering’,
grading in System II; two of these had already existed for many though no instances of irradiation at the limb were recorded.
weeks. The third feature (first observed on Jun 26; No. 7 in the The McIntosh strip maps (of which some are shown in
tables of drifts) coincided in time and place with the aforemen- Figure 7) portray more white spots than dark spots or columns.1
tioned white spot. It could hardly have been a coincidence, and This may have been partly a matter of personal perception, as
the barge (shown in the strip map by McIntosh for Jul 12, shown his original transit records for the following apparition focus far
in Figure 7) disappeared after Jul 23. Rogers (2017) has described more upon EZ(N) white spots than NEB(S) projections, but all his

J. Br. Astron. Assoc. 132, 1, 2022 35
McKim: Jupiter in 1949 & the Revival of the South Equatorial Belt

longitudes agreed closely with those of other observers. The SEBZ Table 3. Drift rates for the 1949 SEB Revival:
dark columns were generally less enduring than the white spots, comparison of sources
as the SEBZ chart shows (Figure 15A).
The original source (dark spot No. 1 in the central branch drift Branch
This BAA McIntosh1 Reese/
tables) – now marked by the f. end of a darkening of the SEBZ analysis Memoir2 (recalculated ALPO3
by McKim)
– showed no appreciable motion. An obvious dark, slanting, p.
end of the disturbance within the SEBZ (and subsequently upon N. branch 9h 54m 00s – 9h 53m 38s –
–73.5 –89.9
the SEB(N)) preceded the original white spot as it moved in de-  11     5
creasing longitude, and the drift of the p. end decreased a little Central branch 9h 54m 09s – 9h 54m 05s 9h 54m 27s
later: see Figure 15A. Slipher photographed the slanting p. end –66.9 –70.2 –53.6
on Aug 10, when it had prograded to λ2 = 97°. The p. end became  29  15   9
less noticeable from mid-September: for example, McIntosh did S. branch 9h 57m 46s 9h 58m 17s 9h 57m 26s 9h 58m 31s
+88.2 +114.4 +77.0 +123.8
not see anything at the extrapolated longitude on Sep 19, though  12    9   7    1
he did record the sloping p. end of a more conspicuous SEBZ
shading (corresponding to dark spot No. 5) some 30° following it. Note: Data for each source are given in the following order: rotation period, Δλ2
What may have been a weak resurgence of the original, always at (°/30 days) and number of features observed. Comments upon these results are
given elsewhere.18
the correct extrapolated longitude, was recorded by Haas on Oct 2
(SEBZ sloping column), Reese on Oct 19 (p. SEBZ shading) and
Focas on Oct 27 (SEBZ thin column). Thus the p. end had faded All the SEB(N) dark spots were first plotted in System I in or-
before it reached the Red Spot Hollow (RSH). der to distinguish the rapidly retrograding features of the Revival
Many SEBZ white spots were quite long-lived; shearing of from near-stationary normal ones. From Jul 23 onwards, many
these spots and the intervening columns (due to the faster drift dark spots showed a rapid and linear positive drift, but there re-
of the SEB(N)) was observed in some cases, being beautifully mained a significant number with normal velocities.
shown by Murayama on Aug 12 and Nov 11 (Figures 20 & 23). Of those features with very small System I drifts, it appears
As early as Aug 10–22, McIntosh (Figure 7) had drawn the first that a number of new spots formed during August–September at
and second leading white spots, elongated in teardrop-fashion. No longitudes just traversed by a sequence of the rapidly retrograding
white or dark spots ever passed the RSH. Revival spots. Not all were well-enough observed to derive drifts,
The average drift rate for the central branch was found to be but the System I chart is highly suggestive of several additional
Δλ2 = –66.9°/mo. In ref. 16 and in Table 3 we have compared our objects moving slightly faster than System I. Activity continued
results with those of McIntosh and the ALPO.1,3 till the end of the observation period, in contrast to the behaviour
At opposition, the GRS was centred at λ2 = 240°, leaving a of the shorter-lived outbreak of the S. branch.
relatively short span of undisturbed SEB(S) and SEB(N) between The creation of the aforementioned new spots with drifts in
it and the source of the Revival to the east. System I parallels the behaviour of the S. branch: in that case,
new normal current spots moving at close to the System II
The f. end of the disturbance & the SEBZ rate had regularly formed as the p. end of the Disturbance had
swept past.
McIntosh claimed that the f. end of the disturbance increased in After obtaining the most satisfactory graphical solution in
longitude from Aug 10 to 25,1 while Reese stated that it was sta- System I, the Revival spots alone were plotted in System II in
tionary from discovery until Aug 24.3 The drift chart (Figure 15A) order to examine their relationship with the longitude of the ini-
explains the disparity: from Aug 22, a number of short-lived dark tial outbreak and with the GRS. Spots 1 & 2 formed close to the
sections of SEBZ had developed west of the main disturbance, initial outbreak, and No. 1 lasted until it reached the f. end of the
and if fewer data had been to hand, a general increase in lon- RSH in late October. Nos. 3–5 formed at lower longitudes and
gitude might have been inferred from them. In fact, there were continued up to the middle of the RSH from mid-October to late
a few areas west of the source longitude that showed a slight November. Nos. 3–4 did not survive the transit of the Hollow, but
positive (retrograding) drift: in particular, a dark p. end during No. 5 did continue for some distance. On Nov 21, ALPO observer
Aug 26 – Sep 2. D. O’Toole showed No. 5 as a massive dark spot invading the
There was no feature that remained fixed in longitude at the Hollow;3 Haas found it still large on Nov 25, and to McIntosh on
source of the outbreak, but a succession of white spots formed Nov 28 it was flattened but extended in longitude. The same spot,
very close to it and moved off in decreasing System-II longitude. now disrupted into a patchy dark semicircle in the central and
A dark f. end of SEBZ shading was often located there, but such northern SEBZ, was seen emerging from the p. end of the RSH by
f. ends (or columns) also moved away from the source. Some p. McIntosh on Nov 30. The apparition then ended.
ends of SEBZ shading were occasionally seen f. the source longi- No. 6 seemed to form at the longitude of the RSH and con-
tude up to λ2 ~ 206° during Aug 19 – Sep 3. White spots always tinued slightly past it, possibly up to – but not beyond – Nov 14,
first appeared within a few degrees of longitude 163°. by when it had reached the precise longitude of the initial out-
break. Nos. 7–10 formed at intermediate longitudes, towards the
The north branch end of the observation period. Nos. 7–8 had significantly lower
System II drifts than all the earlier spots except No. 2. Dark spot
From Jul 23, dark retrograding spots of the Revival appeared upon No. 11 arrived at the Hollow as the apparition ended. McIntosh’s
the SEB(N), one coinciding with the initial SEBZ white spot. By sketch of it on Nov 30 shows it very large,1 and is comparable
mid-September, dark spots were present at all longitudes. with O’Toole’s of No. 5 for Nov 21. Murayama on Dec 4 showed

36 J. Br. Astron. Assoc. 132, 1, 2022
McKim: Jupiter in 1949 & the Revival of the South Equatorial Belt
it nearing the longitude of the centre of the RSH (Figure 24). Thus p. side to the SEB(S) on the f. side, on Aug 23 (complete) and
some of the N. branch spots became large and dark as they passed Sep 2 & 9 (partial, detached). This effect has been observed dur-
due north of the GRS and a large dark patch often appeared to be ing other Revivals.
there, as has been observed in some subsequent SEB Revivals –
including that of 2010, where the same process was recorded.15
The mean drift of N. branch spots was somewhat greater The late SEB disturbance
than that of the central branch: Δλ2 = –73.5°/mo. McIntosh (see
Table 3) obtained a slightly higher value. By early December the SEB was dark for a long stretch upon
both components, and although the SEBZ continued to show
The south branch many interior details, these had now attained a less regular form.
After Oct 26, there was no longer a sign of any especially dark
Between Aug 7 and Sep 27, more than a dozen small dark spots feature at the source longitude. The dark column present on that
located at the southern edge of the SEB(S) were retrograding date subsequently prograded together with adjacent white spots,
within the ~80° stretch of longitude between the source of the leaving nothing behind (Figure 15A). These white spots and the
Revival and the GRS. Longitudes of these typical features were column were still prograding on Nov 29, but there were no further
provided by Hare, Löbering, McIntosh, du Martheray, Murayama observations of their longitudes in the few weeks remaining of
and Reese, while Slipher’s photos of Aug 16 also show them: see the apparition.
in particular Figures 1, 14 & 15B. The average drift rate was Δλ2 =
+88.2°/mo. We compare other sources in Table 3 and in the ‘Notes Colour & intensity changes, 1949 July onwards
& references’ section.18
Following the start of the Revival there was an interval of 18 An increasingly long section of SEB was darkened by the Re-
days before the first S. branch spots were recorded. In 1928,20 vival, while the strong yellow colour of the SEBZ at other lon-
S. branch spots were seen 18 days following the first sighting of gitudes changed to a yellowish-white. On Sep 20, Reese found
the Revival. the revived portion of the SEBZ so dark that the belt rivalled the
The 1949 average drift compares well with other data, although NEB, a comment repeated on Oct 20. The colour intensity of the
it was lower than in many other cases, as this summary (BAA re- SEB(S) – initially a strong copper-red to Reese – was also greatly
sults only, up to 1975) shows: decreased by the Revival, Reese finding it brownish rather than
red or orange during August, and more often grey than brown
Year No. of spots Δλ2 range Δλ2 mean from Aug 19.
(°/mo) (°/mo) Initially equal to the NTropZ, the brightest zone, the STropZ
191921   2 +96 to +101   +98 also became less brilliant as the Revival progressed. In the lon-
192820 17 +84 to +168 +126 gitudes following the RSH, as the p. end of the SEB disturbance
194322   5* +84 to +167 +126
1949 12 +76 to +114   +88
approached the Hollow, the previously bland STropZ was increas-
195223   4 +72 to +124 +100 ingly affected by dusky columns. (See the ‘South Tropical Zone’
195824   6 +96 to +108 +100 section which follows.)
196225   6 +90 to +90   +90
197526 14 +98 to +120 +105
On the other hand, the EZ continued to slowly brighten from
July onwards, especially in the northern half, and by November it
*(two sources) was nearly normal. The effect of the Revival upon the Red Spot is
discussed separately.
There is little evidence that any spot upon the S. branch made the
passage north of the Hollow. Only one spot upon the SEB(N), ap-
parently unconnected with any other SEB(N) feature, was seen
due north of the RSH on Sep 15 (Figure 15B). This corresponded
perfectly with the track of a dark spot on the S. branch (No. 4)
observed five times between Aug 29 and Sep 10, and which dur-
ing Sep 10 upon the drawings of McIntosh and Reese had already
begun to descend the p. shoulder of the Hollow. All other such fea-
tures were destroyed during transit, if they had reached the p. end.
Fortunately, there is no possible confusion with the spots of the N.
branch passing the Hollow, because they encountered it later.
In past Revivals, such as the one of 1943,22 there was clear evi-
dence that spots upon both the S. and N. branches passed through
the longitudes occupied by the RSH.
McIntosh thought that some spots that had reached the p. end
from the S. branch were deflected back along the SEB(N). But
although there was a certain ‘piling up’ of matter at the p. end of
the Hollow (forming an exceptionally large ‘hump’ to Murayama
on Oct 2), there was absolutely no evidence of such deflection. Figure 7. Strip maps showing the start of the 1949 SEB Revival, according to
R. A. McIntosh (356mm refl., Auckland, New Zealand). The vertical dashed line
A number of post-Revival drawings by Reese show a faint shows the longitude of the initial white spot. The continuous lines represent his
dusky band across the GRS, stretching from the SEB(S) on the personal spot identifications. Adapted from the BAA Journal.1

J. Br. Astron. Assoc. 132, 1, 2022 37
McKim: Jupiter in 1949 & the Revival of the South Equatorial Belt
The Reese volcano hypothesis the SEB(S) component still present, and the positive drift rate of
the SEB(S) branch in System II was not as great as in some other
It was the occurrence of the 1949 Revival that had led Reese to Revivals. There were no irradiating white spots, unlike in some
postulate that such outbreaks had a fixed, deep-seated origin at past events. However, there are points unique to this Revival: the
locations that rotated at the rate of the solid nucleus of the planet, fact that the SEB(S) was still distinct, and the strength of the cen-
close to the value of today’s ‘System III’. His first paper appeared tral branch.
in 1953,27 with a later summary by Haas in the ALPO Journal in- The small differential drift rate between the central and north-
cluding illustrations of the 1949 Revival and an SEBZ longitude ern branches probably led to less turbulence between the SEBZ
chart.28 In 1971, Reese revised the number of sources from two and SEB(N), which may in turn have assisted the unusual longev-
to three.29 ity of spots in both currents. In 1943, for instance, Peek had found
We can calculate that Reese’s ‘Source B’ was at System II lon- the pattern of activity so chaotic after a few weeks that periods
gitude 151.8° on 1949 Jun 26 (0h UT),29 when SEB(S) barge No. 7 could be derived only for initial motions of spots.22
was first observed at longitude 148°. On Jul 19 (0h UT), Source B Finally, it seems certain that the 1949 Revival developed from
was at longitude 146.0°, and the initial white spot of the Revival a SEB(S) dark barge, and the barge when first observed coincided
was at 163°. The residuals (O–C) are –4° or +19° respectively. in longitude with that of Reese’s hypothetical Source B.

South Tropical Zone (STropZ) & Great Red
Neither Millar (1950),30 nor the author, could agree that the 1949 Spot (GRS)
Revival was ‘possibly the greatest ever observed’,1 except per-
haps in terms of the number and uniformity of white spots in its The STropZ was bright white and very conspicuous for most of the
central branch. It had only one centre of activity, it developed with apparition, having brightened significantly since 1948 (Table 1).

Figures 8–10. Drawings from 1949 by S. Murayama (Figure 8; 200mm OG, ×180) and E. J. Reese (Figures 9 & 10; 152mm refl., ×200).
8. Jul 23, 15:35 UT, CM1 = 069°, CM2 = 219°; S. Temperate white oval BC east of the GRS (with lighter interior); NTZ white oval p. the CM.
9. Jul 27, 02:47 UT, CM1 = 232°, CM2 = 356°; note the STZB and NTropZB; many other fine details and high-latitude belts.
10. Jul 28, 02:15 UT, CM1 = 011°, CM2 = 127°; the p. end of the SEB Revival, with two SEBZ white spots, is shown at an early stage in its development. (Despite ap-
pearances, there were no physical connections between the EZ and SEBZ bright features.)

Figures 11–13. Drawings in 1949 by S. Murayama (200mm OG, ×180 for Figures 11 & 12; 150mm refl., ×148 for Figure 13).
11. Aug 9, 11:40 UT, CM1 = 091°, CM2 = 113°; part of the SEB Revival is shown.
12. Aug 29, 10:40 UT, CM1 = 334°, CM2 = 203°; small dark SEB(S)s spots in the S. branch of the Revival are shown.
13. Aug 29, 11:30 UT, CM1 = 004°, CM2 = 234°; S. Temperate white oval DE is approaching conjunction with the GRS; the dark spots upon the SEB(N) N. edge and
EZ(S) were moving in the normal S. Equatorial Current.

38 J. Br. Astron. Assoc. 132, 1, 2022
McKim: Jupiter in 1949 & the Revival of the South Equatorial Belt

The GRS was initially very faint. Starting with Haas’ first obser-
vation of Feb 18, all observations from February to April showed
the RSH but not the GRS, or at most a hint of shading in the
SW quadrant. During his first observation (Figure 3), on Mar 24,
Reese noted how the STropZ columns bounding the RSH had
faded somewhat since 1948. They faded further over the weeks
which followed, so that only a faint sign of the f. one was vis-
ible by May 1. The Hollow had the same relative intensity as the
The GRS was first observed on May 8 by Murayama and on
May 22 by Reese. The STropZ columns had vanished. The GRS
darkened during June–July, remaining an easy object throughout
August. It was quite conspicuous in Slipher’s July photographs
(Figure 1). To Reese (152mm refl.), it had an orange-ochre tint,
but McIntosh with his large aperture (356mm) was able to make
out its characteristic pink or salmon colour from July to Septem-
ber. Hare (178mm refl.) described it as pink, May to July, and
du Martheray (135mm OG) found a reddish or lilac tint, July to
September. Using a 203mm OG, Murayama (from Jul 24 until the
Hollow aspect replaced the GRS) showed the edge of the GRS to
be darker than the interior (Figures 8 & 13), an aspect also shown
by du Martheray with his smaller aperture (Figure 3).
The SEB Revival began on Jul 19, and in September the col-
umns in the STropZ outlining the p. and f. ends of the Hollow
darkened again.
Reese suspected the GRS to be fading on Aug 30, and this had
become obvious by Sep 21. On Sep 10 (Figure 3), 19 & 21 he ob-
served a bright spot covering the Np. part of the Spot, with a light-
er spot in the Nf. quarter on the first date. A brighter area in the Np.
Figure 14. Strip sketches of the 1949 SEB Revival S. branch spots approaching
part was observed by du Martheray (Figure 3) on Sep 3, who had the GRS. (Redrawn by the author.)
also seen some patchy lightness in the N. part in late July. A Np. (A) Aug 25, by E. E. Hare (from Reese E. J., J. Assoc. Lunar Planet. Obs.,
light area was also seen by Haas, while Hare described perhaps 12(10–12), 139 (1959)).
the same phenomenon as an elongated white rift (which betrayed (B) Sep 2, by E. J. Reese (from a drawing at 03:57 UT, CM2 = 201°).
no sign of rotation) within the Spot during Sep 10–22. These were (C) Sep 10, by E. J. Reese (a strip sketch made at 00:48–02:44 UT, CM2 =
the first instances of white cloud (perhaps from the STropZ) start- 208–279°).
ing to cover the GRS; the Spot progressively faded from the Np. (D) Sep 19, by R. A. McIntosh.1
quarter. On Oct 10, Reese noted how the RSH had become more
prominent than the GRS. Some observers saw a faint portion of the RSH or the NTropZ. Focas also sketched the STropZ activity
the GRS remaining within the Hollow until Oct 21, while others on Oct 27, when some 40° f. the RSH there was a massive hump
– like du Martheray on Oct 12 (Figure 3) – had already ceased to upon the SEB(S), extending into the STropZ. The same feature
see any part of it. Murayama too, from Oct 16, could see only the was recorded again by Reese on Nov 9. After mid-August, similar
strongly outlined Hollow. dusky columns, up to ~140° p. the RSH, were observed to form
The Spot showed no colour to McIntosh on Oct 3. He then (Figure 14B). Again, the one closest in longitude to the source of
saw a pink tint again, but the Hollow was white during Oct 29 the Revival – No. 2 – was the first to appear. Some lighter ovals
to Nov 18. On Nov 28 – his last observation – the pink hue re- were seen between these columns by Bateson and Reese.
turned again, but his drawing still shows the Hollow rather than Shading had appeared in the STropZ following the 1943 SEB
the Spot. Revival.31 The zone would remain slightly less bright than usual
As first noticed by Reese on Sep 26, a broad dusky shading in 1950, although no specific dusky features remained; nor did it
(No. 4 in the tables) developed in the S. part of the STropZ (south show any appreciable warm tone.
of the STropZB) following the Spot; it became conspicuous Like Reese, Focas also made observations of a great NEBs
enough for some observers (in poor seeing) to mistake it for the festoon that stretched across the EZ to the SEB, but to Focas it
GRS. This unusual aspect was noticed by Alcock, Reese (Figure 3, appeared to reach even further south. Thus on Aug 3, Sep 3 and
for Oct 18) and Wildey (Figure 19). Three other broad dark col- Oct 27 the highly curved festoon seemed to Focas to continue into
umns, which showed a slight positive drift in System II, developed the SEBZ, even as far as the aforementioned SEB(S) hump on
in the ~100° stretch of longitude f. the Hollow, and chronologi- the latter date. Such apparent – but dynamically impossible – as-
cally they formed in order of increasing distance f. the source of sociation can be explained by the ‘canal effect’ that misleads the
the SEB Revival. (See Figures 3, 17 & 22.) This activity in the eye, as there were many columns in the SEBZ which must fre-
STropZ led to a darkening of the zone around mid-October, espe- quently have been in conjunction with the numerous EZ festoons:
cially f. the RSH. This aspect was well shown by Slipher’s pho- see Figures 10 & 18 for example. Furthermore, the acceleration
tographs of Oct 11 (Figure 1), where the STropZ was darker than of many SEB(N) features by the Revival, and the consequent
J. Br. Astron. Assoc. 132, 1, 2022 39
McKim: Jupiter in 1949 & the Revival of the South Equatorial Belt

Figure 15. Spot charts for the 1949 SEB Revival (in System II).
(A) (Above.) The SEBZ central branch white and dark spots. The initial white spot No. 1 (1w) of the Revival was associated with dark spot (‘barge’) No. 7 in the SEB(S)
normal current, which is also illustrated here. Dark spot No. 1 (1d) was the p. end of the Revival in the SEBZ.
(B) (See opposite page.) The SEB(S) S. branch dark spots. No. 4 continued into the Red Spot Hollow as an SEB(N) spot that was not associated with the N. branch of the
Revival. Successive spots are shown alternately in black or red for clarity.
Each chart shows the GRS/RSH longitudes as five-day means (15-day means after mid-November). The scales of charts (A) and (B) are different.

reduction in the differential velocity with the EZ, might enable a During November and early December, the longitude of the centre
greater degree of connectivity between EZ festoons and the SEBn. of the Hollow increased slightly. From visual transits, the mean
The GRS was centred at longitude 237–238° during May and length of the GRS was 26.5° and that of the RSH, 29°. The GRS
June. This slightly increased to 240° at opposition on Jul 19 (com- was 27° long on Slipher’s Jul 18 photo (Figure 2B).
pare 228° for the RSH at opposition in 1948). Its longitude subse- It was during the 1949 opposition that the first evidence of cir-
quently was influenced by the SEB Revival, and as the spots of the culation around the periphery of the GRS was obtained.32
retrograding S. branch reached the Hollow, its longitude increased
during the second half of August to reach 247° by the end of the
month and remained close to this value throughout September. In South Temperate Belt (STB)
early October, as the prograding branch approached the GRS, its
longitude decreased to 243° – slightly greater than the opposition This was dark and indented on its S. edge by the three long-lived
value – and from this point the Hollow aspect became dominant. south-temperate white ovals. The belt was darker at their p. and

40 J. Br. Astron. Assoc. 132, 1, 2022
McKim: Jupiter in 1949 & the Revival of the South Equatorial Belt

South South Temperate Belt
The belt designated as the SSTB was quite
bland. It seems to have been an SSSTB, given
its latitude (see Table 2), and the fact that some
conspicuous darker spots upon its north edge
(Figures 1, 8, 9 & 16) moved with drifts typical
of the South South Temperate Current. South
of this belt was a somewhat shaded zone,
which was not conspicuous visually.

South Polar Region (SPR)

This region showed little detail. Another far
southern belt was occasionally reported and
was photographed by Slipher.

Satellite observations

On 1949 Mar 3, satellites I–IV would all have
been invisible for nine minutes (one being in
transit, one eclipsed and two occulted), but this
rare event was apparently not observed.34
On Apr 12, Haas (152mm refl., ×188) re-
corded the occultation of a faint star by satellite
II, from about 11:16.6 to 11:23.9 UT.
Slipher’s photograph of Jul 15 (Figure 1)
shows a double transit and shadow transit.
An anomalous occultation disappearance
(OcD) of Io was seen by Reese (152mm refl.,
×240) on the night of Aug 7/8. ‘As satellite I
was being occulted by Jupiter’s W. limb, the
Figure 15. (B) See opposite page for caption. visible segment of the satellite disk became
smaller and smaller until only a glowing point
projected beyond the limb. The point dwindled
f. ends and contained other darker spots and sections, in addition and disappeared near 11:39.8 p.m. [Eastern Standard Time; hence
to a few small interior white spots that moved with slower drift 2nd contact was at Aug 8, 04:39.8 UT]. However, within a second
rates than the ovals. or two it reappeared but … now appeared as a full disk, pale and
seemingly entirely within Jupiter’s limb. This appearance lasted
about 10 seconds and then it faded…’ WinJUPOS predicts 2nd
South Temperate Zone (STZ) contact at 04:41.0 UT, just one minute later than Reese’s tim-
ing. This type of anomaly (an optical illusion?) has previously
The STZ contained the long-enduring white ovals FA, BC and DE, been reported.35
which had been followed since 1939–’41 and which in the late On Aug 24, Haas made a detailed drawing of satellite III, with
1940s still occupied considerable stretches of longitude.33 Oval FA the aid of the 300mm OG of Griffith Observatory, Los Angeles.
is well shown in Figures 2D, 10 (p. limb), 11 & 22 (f. side); oval This shows brighter areas near the poles and several albedo mark-
BC in Figures 1 (Jul 15 & Aug 16), 2B–C, 3 (left-hand column), ings. Reese also occasionally saw the largest of the dark markings.36
4, 5, 8, 12 & 13; and oval DE in Figures 3 (right-hand column), Mutual phenomena were again observable in 1949: although
4, 8, 12–14 & 17. The ovals exhibited typical drifts, with BC no predictions had been issued, a partial eclipse of satellite II by
and DE relatively close together (see Figures 4, 8, 12 & 13). The III was seen by Haas, Hare and Reese on Sep 25. At 01:50 UT they
edges of BC and DE were 32° apart in mid-May, but only 18° by saw the shadows starting to merge, and Reese at around 02:09 UT
mid-October; the ovals were separated by an STZ dusky column. found the shadow of II due north of and overlapping that of III.
Oval DE was still considerably longer than the GRS WinJUPOS gives 01:58 and ~02:14 UT for the critical times.
(Figure 13). The drift of oval DE was temporarily retarded during An occultation of II by III was recorded by Haas and Hare
its August–September conjunction with the GRS. (178mm refl., ×200) on Oct 16: more details were given in ALPO
A thin STZB was sometimes recorded by Hare and Reese interim reports by Reese.2 The impression that the event was
(Figure 9) under the best seeing conditions. nearly central is perfectly confirmed by WinJUPOS.

J. Br. Astron. Assoc. 132, 1, 2022 41
McKim: Jupiter in 1949 & the Revival of the South Equatorial Belt

Drift rates / rotation periods N. Equatorial Belt N. component/ N.Tropical Zone (N.
Tropical Current)
These periods supersede (and significantly amplify) those pub-
lished in the summary table in the 1960 BAA Memoir,2 though Description Limiting dates No. obs. Longitude Δλ2 (°/30 days)
at oppn.
the latter (deduced from a smaller data set) are in good accord.
In several instances we have differed with identifications by the 1 c. d. spot Jul 20 – Aug 5   6 111 –20.8
2 c. w. spot Apr 21 – May 30   4 (126)   +1.5
ALPO,3 but on the whole, agreement is very good. Peek has use- 3 c. d. spot Apr 21 – Aug 9 12 130   –4.0
fully summarised BAA rotation periods up to 1948.36 4 c. w. spot Apr 18 – Jul 15   6 (150)   –1.7
3,556 longitude measurements were available, and 2,308 were 5 c. w. spot Apr 10 – Nov 21 33 177 –14.7
6 c. w. spot Sep 10 – Nov 1   4 (210)   +1.5
used in deriving drift rates. In the following tables, Δλ1 and Δλ2 7 c. w. spot Jun 24 – Jul 30   5 212   +3.2
denote the rates of change in longitude of features, in degrees per 8 c. w. spot Apr 22 – May 21   4 (266)   –5.8
30 days; c., p. and f. mean centre, preceding and following ends, 9 c. w. spot Jul 14 – Dec 4 19 286   –4.3
10 c. d. spot Aug 27 – Oct 16   5 (290)   –1.3
and d. and w. mean dark and white. 11 c. d. spot Mar 27 – Oct 24 36 322   –5.9
12 c. w. spot May 2 – Jun 2   3 (323) –12.5
13 c. w. spot Jul 28 – Sep 9   5 (334) –12.0
N. N. N.Temperate Belt (N. N. N.Temperate Current) Mean: –5.9
(9h 55m 32s)
Description Limiting dates No. obs. Longitude Δλ2 (°/30 days)
at oppn. The dark spots were mostly projections from the NEBn; No. 11 was a
c. d. spot Jul 4 – Jul 18 3 (214) –4.7
conspicuous ‘barge’. The N. Tropical Current mean drift rate was slight-
ly lower than average (as for 1948), and considerably slower than for
Mean: –4.7 1950 (when there were more – and larger – barges).
(9h 55m 34s) No. 2 may have revived, Jul 20 – Aug 10.
No. 6 may have been a revival of No. 7, No. 9 of No. 8, and No. 13
This is necessarily a tentative period, but the observations were extreme- of No. 12.
ly consistent. No. 9 was large, as wide as the NTropZ, Oct 22 – Nov 10.

N. N.Temperate Belt (N. N.Temperate Current A) N. Equatorial Belt centre (NEBZ)

Description Limiting dates No. obs. Longitude Δλ2 (°/30 days) Description Limiting dates No. obs. Longitude Δλ2 (°/30 days)
at oppn. at oppn.
1 f. d. section Jul 9 – Sep 24   8 029 +1.8 1 p. w. spot Jul 2 – Aug 12 6 204 –133
2 f. d. section Jun 23 – Sep 2* 10 088 +0.0 2 c. w. spot Jul 9 – Aug 12 5 216 –130
3 c. w. oval Jul 15 – Aug 16   6 210 +0.0 3 f. w. spot Jul 2 – Aug 12 5 228 –124
4 p. d. section May 9 – Nov 14 27 246 +3.8 4 c. w. spot Sep 2 – Sep 21 9 236   –93
5 f. d. section Aug 27 – Nov 10† 11 (306) +1.5
Mean: –120.0
6 p. d. section May 2 – Oct 11 13 334 +0.5
(9h 52m 57s)
Mean: +1.3
(9h 55m 42s) The mean period (close to the North Intermediate Current average)
was much faster than that observed in 1948, and somewhat faster than
* About 40° long. † Also observed May 12–24.
for 1950.
Nos. 1–3 (representing one feature) consisted of two components on
The f. ends of dark sections of the NNTB were less stable than their p. Ball’s drawing of Aug 11.
ends (an effect to be repeated in 1950).
Nos. 4 & 5 and Nos. 6 & 1 were the p. and f. ends of the same feature.

N. Equatorial Belt S. component / N. Equatorial Zone
N.Temperate Belt & N.Temperate Zone (N.Temperate (N. Equatorial Current)
Current A) Description Limiting dates No. obs. Longitude Δλ1 (°/30 days)
at oppn.
Description Limiting dates No. obs. Longitude Δλ2 (°/30 days)
at oppn. 1 c. w. spot Jul 9 – Oct 16 26 019 –10.3
2 c. d. spot Mar 18 – Dec 12 40 030 –11.1
1 p. d. section Jun 6 – Oct 3 14 103 +18.2 3 c. d. spot Apr 20 – Dec 1 38 058 –11.5
of NTB & NTZB 4 c. w. spot Jun 2 – Oct 3 13 071 –12.2
2 f. d. section May 6 – Oct 19 15 177 +13.5 5 c. d. spot Apr 6 – Nov 29 23 082 –12.2
of NTB and NTZB 6 c. w. spot Jun 2 – Jul 21   7 102 –5.1
3 c. w. spot Jul 3 – Sep 10 18 182 +14.5 7 c. w. spot Sep 8 – Oct 9   4 (110) –18.6
in NTB 8 c .d. spot Feb 19 – Dec 4 43 114 –9.5
4 p. lighter section Jul 4 – Nov 2 14 249 +17.2 9 c. w. spot Jul 9 – Nov 9 16 129 –6.9
of NTZ 10 c. d. spot Mar 15 – Nov 27 34 153 –9.2
11 c. d. spot Aug 14 – Sep 22   4 (157) –0.2
Mean: +15.8 12 c. w. spot Jul 19 – Oct 10 12 169 –6.1
(9h 56m 02s) 13 c. w. spot Jul 3 – Sep 20 13 179 –4.9
14 c. d. spot Mar 24 – Nov 30 43 188 –6.9
15 c. w. spot May 2 – Jun 8   4 (196) –0.5
Nos. 1–2 comprised the North Temperate Dislocation between the NTB 16 c. w. spot Jul 22 – Oct 11 15 (208) –6.2
and NNTB. No. 4 decelerated after mid-August. Continued on opposite page

42 J. Br. Astron. Assoc. 132, 1, 2022
McKim: Jupiter in 1949 & the Revival of the South Equatorial Belt

Continued from previous page Continued
Description Limiting dates No. obs. Longitude Δλ1 (°/30 days) Description Limiting dates No. obs. Longitude Δλ2 (°/30 days)
at oppn. at oppn.
17 c. d. spot Apr 7 – Nov 7 40 239 –7.6 3 c. d. spot Sep 25 – Dec 11   6 (068) +7.2
18 c. w. spot Apr 23 – Sep 25 28 250 –6.8 4 c. d. spot Aug 23 – Oct 1   6 (070) +13.8
19 c. d. spot Mar 31 – Aug 8 29 264 –4.8 5 c. d. spot Aug 1 – Sep 7   8 (128) + 9.6
20 c. w. spot Apr 7 – Jul 27 12 272 –12.6 6 c. d. spot Jul 23 – Sep 7   7 (148) +7.8
21 c. d. spot Jul 20 – Sep 27 20 (286) –20.8 7 c. d. spot Jun 26 – Jul 23   8 164 +21.4
22 c. w. spot Jul 4 – Sep 25 17 289 –15.9 8 c. d. spot Jul 2 – Oct 22 18 300 + 5.2
23 c. d. spot Aug 15 – Nov 21 21 (296) –6.2 9 c. d. spot Sep 19 – Oct 12   8 (325) +7.6
24 c. w. spot Jul 24 – Nov 14 20 (300) –7.8
25 c. d. spot Mar 20 – Nov 10 41 312 –4.8 Mean: +9.3
26 c. w. spot Jun 8 – Jul 26   5 321 –16.4 (9h 55m 53s)
27 c. d. spot Mar 27 – Jul 25 19 (339) –6.5 Mean without No. 7: +7.8 (9h 55m 51s)
28 c. d. spot Sep 16 – Nov 24   6 (339) –9.6
29 c. w. spot Jul 24 – Nov 8 14 (342) –1.8 All spots lay within the S. component of the SEB. No. 7 was the barge
30 c. w. spot Mar 27 – Jun 8   9 (358) –5.9 from which the initial white spot of the Revival developed on Jul 19.
31 c. d. spot Mar 27 – Dec 5 42 359 –8.2
Nos. 1, 2, 8 & 9 also existed prior to the Revival: as the latter’s p. end
Mean: –8.6 swept through them, they continued approximately on their courses.
(9h 50m 18s) Nos. 3–6 (as well as several other, less well-observed spots) formed sub-
sequently, and were first observed shortly after the p. end had prograded
No. 7 was probably a revival of No. 6, as was No. 16 of No. 15. No. 19 past their longitudes.
merged with No. 21. No. 21 had a very rapid initial drift (~ –36°/mo) No. 2 extrapolates back to a feature observed during Mar 27 – Apr 6.
during Jul 20–31, but suddenly slowed to ~ –16°/mo thereafter. No. 5 probably continued till Nov 28.
The path of No. 8 coincides with that of column No. 6 in the S. Tropi-
cal Current.
Equatorial Band / S. Equatorial Zone (central branch,
Equatorial Current) S. Equatorial Belt N. component: N. branch of Revival
Description Limiting dates No. obs. Longitude Δλ1 (°/30 days)
Description Limiting dates No. obs. Longitude Δλ1 (°/30 days)
at oppn.
on Oct 19
1 c. d. spot Jun 23 – Sep 7 14 027 –11.5
1 c. d. spot Jul 23 – Oct 24 19 064 +145
2 f. d. spot Jul 3 – Sep 2 12 263   +0.0
2 c. d. spot Jul 28 – Sep 4 13 (170) +178
3 f. d. spot Jul 4 – Aug 3   6 306   +9.2
3 c. d. spot Aug 25 – Oct 21 14 049 +143
4 c. w. spot Jul 20 – Aug 1   4 311 +11.0
4 c. d. spot Sep 21 – Nov 7 12 088 +141
Mean: +2.2 5 c. d. spot Sep 21 –Nov 30 17 119 +155
(9h 50m 33s) 6 c. d. spot Oct 8 – Oct 21   5 024 +160
7 p. d. spot Oct 22 – Nov 18   8 (320) +165
No. 1 was a dark spot located upon the EB/EZ(S) and showed the same 8 f. d. spot Nov 9 – Nov 28   4 (329) +174
9 c. d. spot Nov 11 – Nov 18   3 (268) +144
drift as a darker section of the SEB(N), which was in conjunction with it 10 c. d. spot Nov 11 – Nov 30   4 (282) +156
during August–September. 11 c. d. spot Nov 26 – Dec 6   5 (158) +156
No. 4 was a white spot in the EZ(S) which formed a gap in the EB.
Mean (omitting Nos. 8–10): Δλ1 = +155.4; Δλ2 = –73.5
(9h 54m 00s)

S. Equatorial Belt N. component (S. Equatorial Current Spots in the N. Branch were numbered in order of (a) date of appearance
(normal)) and (b) increasing longitude. The longitudes quoted above were more
conveniently referred to a later date than opposition.
Description Limiting dates No. obs. Longitude Δλ1 (°/30 days) No. 1 was the dark spot coincident with the initial SEBZ white oval
at oppn. of the Revival.
1 c. d. spot Aug 1 – Sep 21   8 (027) –13.4 No. 6 may have continued till Nov 14.
2 c. d. spot Aug 8 – Sep 26   8 (035)   –5.8
3 c. d. spot Sep 22 – Oct 10   7 (172) –16.9
4 c. d. spot Sep 15 – Oct 8   7 (153)   +0.0
5 c. w. gap Jul 1 – Jul 19   4 180   +0.0 S. Equatorial Belt Zone: central branch of Revival
6 c. d. spot Sep 4 – Sep 24   6 (203) –16.1 Dark spots
Mean: – 8.7 Description Limiting dates No. obs. Longitude Δλ2 (°/30 days)
(9h 50m 18s) on Oct 1
1 p. d. spot Jul 23 – Oct 27 22 343 –70
Nos. 1 & 2 were moving alongside EB dark spot No. 1 in the preced- 2 p. d. spot Jul 26 – Aug 28 14 (341) –75
ing table. 3 f. d. spot Aug 19 – Sep 7 4 (084) –56
4 f. d. spot Aug 22 – Sep 2 5 (344) –74
5 p. d. spot Aug 28 – Nov 3 13 005 –71
6 p. d. spot Oct 8 – Oct 20 3 (171) –68
S. Equatorial Belt S. component: normal current 7 p. d. spot Oct 10 – Nov 10 5 (042) –55
8 c.d. spot Oct 27 – Nov 10 3 (054) –80
Description Limiting dates No. obs. Longitude Δλ2 (°/30 days) 9 p. d. spot Nov 1 – Nov 22 4 (200) –52
at oppn. 10 p. d. spot Nov 3 – Nov 18 3 (039) –74
Mean for dark spots (omitting Nos. 3, 6, 8–10): –69.0
1 c. d. spot May 1 – Nov 18 29 016 +5.5
(9h 54m 06s)
2 c. d. spot Jun 23 – Nov 18 22 035 +5.9

J. Br. Astron. Assoc. 132, 1, 2022 43
McKim: Jupiter in 1949 & the Revival of the South Equatorial Belt

White spots The longitudes quoted above were more conveniently referred to a lat-
Description Limiting dates No. obs. Longitude Δλ2 (°/30 days) er date than opposition. All spots protruded into the STropZ from the
on Oct 1 SEB(S) S. edge and showed extremely constant drifts. Larger dark spots
(‘barges’) within the S. component were found to be moving with small,
1 c. w. spot Jul 19 – Sep 2 23 (333) –65 non-Revival System II drifts, and have been tabled separately under
2 c. w. spot Aug 1 – Sep 7 16 005 –75
‘S. Equatorial Belt S. component: normal current’.
3 c. w. spot Aug 9 – Sep 19 15 (017) –76
4 c. w. spot Aug 15 – Sep 26   9 (037) –70
5 c. w. spot Aug 25 – Oct 10   7 061 –78
6 c. w. spot Aug 25 – Oct 18 12 081 –62
7 c. w. spot Aug 30 – Oct 18 11 097 –56
Great Red Spot & Hollow
8 c. w. spot Aug 26 – Nov 18 12 110 –58
9 c. w. spot Sep 10 – Nov 18   9 119 –66 Description Limiting dates No. obs. Longitude Δλ2 (°/30 days)
10 c. w. spot Sep 10 – Nov 6   9 130 –59 at oppn.
11 c. w. spot Sep 19 – Nov 18 13 140 –68 p. end GRS May 8 – Oct 8 69 227 +2.8
12 c. w. spot Sep 29 – Nov 18 12 148 –66 c. GRS May 8 – Oct 8 73 240 +2.8
13 c. w. spot Oct 3 – Nov 30 10 (155) –59 f. end GRS May 9 – Oct 8 69 254 +2.8
14 c. w. spot Oct 16 – Oct 30   4 (178) –75
15 c. w. spot Oct 21 – Nov 28   8 (184) –72 Mean: +2.8
16 c. w. spot Oct 22 – Nov 28   7 (187) –63 (9h 55m 44s)
17 c. w. spot Oct 26 – Nov 11   3 (196) –63
18 c. w. spot Oct 26 – Nov 28   7 (206) –67 p. end Hollow Mar 14 – Dec 20 96 224 +1.6
Mean for white spots (omitting Nos. 14, 17): –66.2 c. Hollow Mar 14 – Dec 16 68 239 +1.6
(9h 54m 10s) f. end Hollow Feb 18 – Dec 16 68 254 +1.6
Mean (all spots): –66.9 Mean: +1.6
(9h 54m 09s) (9h 55m 43s)

The longitudes quoted above were again more conveniently referred to
As described in the text, the GRS had a small positive drift in longitude
a later date than opposition.
until opposition, and the rate of drift increased more rapidly after the
Spots in the central branch were numbered in order of (a) date of
start of the SEB Revival; after reaching a maximum in late August, its
appearance and (b) increasing longitude. The average drift rates of the
longitude returned by October to a value slightly greater than that at op-
white spots and dark spots were insignificantly different. Similar drifts
position. The longitude of the RSH increased slightly during November
were suggested for several other, less well-observed spots.
and December.
Dark spot No. 1 was the p. end of the advancing front of the Re-
vival within the SEBZ, whose negative drift rate sharply decreased after
Jul 28. It was continuously present until Sep 10, after which there was
a faint resurgence (Oct 2–27). DS No. 2 seems to have run into No. 1 S.Tropical Zone (S.Tropical Current)
after Aug 28. DS No. 5 was normally the p. end of SEBZ shading, but
sometimes appeared as a column. Description Limiting dates No. obs. Longitude Δλ2 (°/30 days)
White spot No. 1 was the original white spot, whose initial negative at oppn.
drift rate (Δλ2 = –50°/mo for Jul 19 – Aug 15) slightly increased after
1 c. d. column Oct 10 – Dec 12 3 (069) +7.0
mid-August. Nos. 2 & 3 behaved similarly.
2 c. d. column Aug 19 – Nov 6 5 (176) +5.1
As indicated by question marks upon the chart (Figure 15A), WS 3 c. d. column Sep 2 – Oct 19 7 (191) +10.4
No. 2 may have been observed again during Sep 29–Oct 3, and WS 4 f. d. shading Oct 2 – Dec 16 7 (250) +2.5
No. 4 from Oct 17–24. 5 c. d. column Sep 8 – Nov 10 7 (254) +9.2
WS No. 7 may have continued again during Nov 8–18. 6 c. d. column Sep 18 – Dec 8 10 (304) +4.9
WS Nos. 9–13 were not well observed for 2–3 weeks after Oct 3, but
Mean: +6.5
their constant spacing and very similar, constant drifts tend to validate (9h 55m 50s)
the identifications given.
White spot No. 18 and dark spot No. 9 were the last ones to be seen to
The identification of No. 1 is tentative, but precedent and the closeness
form close to the source of the Revival.
of other drifts support it.
An unusual feature is the area of the chart between DS No. 7 and WS
Column No. 3 ran into the p. end of the RSH, but the p. end of the
No. 7, which is devoid of detail after Oct 22, but not because of a lack
column remained visible until Nov 24.
of observations.
No. 4 was the shading in the south of the zone, which was sometimes
mistaken for the GRS.
S. Equatorial Belt S. component: S. branch of Revival No. 6 was the most prominent feature (for some time exceeding 20° in
length); its path coincided with that of a pre-existing SEB(S) dark spot
Description Limiting dates No. obs. Longitude Δλ2 (°/30 days) (normal current). A further dusky column followed it during November.
on Sep 1 (0h) White spots in the STropZ(N) were occasionally seen either side of
1 c. d. spot Sep 10 – Sep 22 6 (177) +76 No. 3, or between No. 4 and the RSH.
2 c. d. spot Sep 2 – Sep 10 6 (185) +92
3 c. d. spot Sep 2 – Sep 10 4 (190) +99
4 c. d. spot Aug 29 – Sep 15 7 198 +96
5 c. d. spot Aug 26 – Sep 7 5 208 +93 S.Temperate Belt (S. & S.S.Temperate Currents)
6 c. d. spot Aug 29 – Sep 2 3 212 +100
7 c. d. spot Aug 10 – Sep 3 13 220 +84 Description Limiting dates No. obs. Longitude Δλ2 (°/30 days)
8 c. d. spot Aug 21 – Aug 25 3 (225) +83 at oppn.
9 c. d. spot Aug 21 – Aug 26 4 (236) +97
10 c. d. spot Aug 22 – Aug 26 4 (246) +114 1 p. w. spot Jul 28 – Nov 10 12 (013) –25.0
11 c. d. spot Aug 14 – Aug 22 4 (251) +108 2 p. oval FA Mar 28 – Dec 4 17 060 –23.8
12 c. d. spot Aug 7 – Aug 15 4 (285) +110 3 f. oval FA May 6 – Dec 4 26 088 –23.4
4 f. d. section Mar 19 – Nov 26 32 145 –24.4
Mean (omitting Nos. 3, 6, 8–12): +88.2 5 c. w. spot May 26 – Jul 20 7 (151) –27.2
(9h 57m 42s)
Continued on opposite page

44 J. Br. Astron. Assoc. 132, 1, 2022
McKim: Jupiter in 1949 & the Revival of the South Equatorial Belt
McIntosh’s original records, but the author obtained nearly 400 longitude
Continued from previous page measurements from his published strip maps.
2 In 1949 October, D. W. Millar succeeded B. M. Peek as Director. He had
6 f. w. spot May 28 – Jul 20 9 (158) –26.1 already been Assistant during 1948, responsible for collecting observations.
7 f. w. spot Aug 6 – Aug 23 4 (169) –14.6 He subsequently became seriously ill and was succeeded by Dr A. F. O’D.
8 p. d. section Aug 19 – Oct 8 7 (187) –30.2 Alexander. Dr Alexander dealt with the 1943–’47 backlog, Millar wrote up
9 p. oval BC May 14 – Oct 23 26 204 –20.2 1948, and the new Assistant W. E. Fox concentrated upon the observations for
10 f. oval BC May 12 – Nov 6 27 234 –21.9 1951–’52 onwards. The 1949 and 1950 oppositions were overlooked. Publica-
11 c. column Jul 4 – Aug 24 4 239 –20.9 tion of these reports now means that every opposition from 1891 up to and
12 p. oval DE May 12 – Oct 11 19 262 –22.4 including 1952–’53 has been fully discussed in the Memoirs or in the Journal.
13 f. oval DE Mar 27 – Oct 26 33 305 –22.6 Some oppositions of the later 1950s were not reported, though summary rota-
14 c. w. spot Jun 20 – Aug 8 4 328 –12.4 tion periods for all years up to 1958 – including 1949 – were calculated and
Mean: –22.5 published in a table in a BAA Memoir: Fox W. E., Mem. Brit. Astron. Assoc.,
(9h 55m 10s) 39, part 1, p.32f (1960).
3 For the final ALPO report, see Reese E. J., J. Assoc. Lunar Planet. Obs.,
12(10–12), 135–143 (1959). Several interim reports were published by Reese:
White spots Nos. 1 & 13 and the white S. Temperate ovals FA, BC and ibid., 3(8), 4–7; (9), 11–13; (10), 8–10; (11), 5–7 and (12), 2–4 (1949), as well
DE lay at the S. edge of the STB. The white ovals moved with a drift as 4(2), 7–9 (1950).
characteristic of the S. S. Temperate Current. BC & DE were separated 4 Mrs Teddie Moreno of NMSU Library kindly scanned the logbooks of Haas
and Reese.
by a dusky column in the STZ: No. 11. Oval DE was briefly retarded in 5 Mr K. Horikawa, Director of the ALPO Japan Jupiter Section, was able to sup-
its drift in early September as a result of its conjunction with the GRS. ply a full set of Murayama’s 1949 records, including 72 drawings. (In 1949,
White spots Nos. 5/6, 7 & 14 were small ovals within the STB, and Murayama had sent only three drawings and a few CM transits to the BAA.)
their average drift was less rapid than that of the white S. Temperate ovals. 6 G. Ruggieri also published a short note: ‘Giove nell’opposizione 1949’,
Coelum, 18, 13–16 (1950). This paper and an English translation were kindly
sent by Gianluigi Adamoli.
7 See Peek B. M., J. Brit. Astron. Assoc., 59, 225 (1949) and Millar D.W., ibid.,
S. S.Temperate Belt (S. S.Temperate Current) 60, 216 (1950).
8 Notebooks or papers of these observers are held in the BAA Archives.
Description Limiting dates No. obs. Longitude Δλ2 (°/30 days) 9 The 1949 observations of J. H. Focas (or Phocas) appeared in National Obser-
at oppn. vatory of Athens – Greece, Bulletin of the Astronomical Institute, no. 1, 11–13
(1950), with a few illustrations in La Physique des Planètes, Les Congrès et
1 c. d. spot Jul 15 – Sep 2 3 180 –27.2 Colloques de l’Univesité de Liège, Universite de Liège, 24, 535–540 (1962).
2 c. d. spot Jul 9 – Aug 27 5 357 –26.2 No replies to enquiries concerning his original observations were received
from the National Observatory of Athens.
Mean: –26.7
10 Through the kindness of Mr S. Fischer and the Swiss Astronomical Society, we
(9h 55m 04s)
received copies of all 66 of du Martheray’s drawings and observations. This
observer also published brief notes in Bull. Soc. Astron. de Suisse (Orion),
no. 24, pp. 588–589 and no. 25, p. 28 (1955).
Though the observations are few, the mean drift agrees precisely with 11 These data were supplied on a CD archive prepared by H-J. Mettig. A brief
that for four spots observed by the ALPO.3 note by W. Löbering in Astron. Nachrichten, 280(4), 157–160 (1951) mentions
his personal work in 1949 and 1950, while coloured drawings of the Great Red
Spot area in both years can be found in Löbering W., ‘Jupiterbeobachtungen
von 1926 bis 1964’, Nova Acta Leopoldina, 34, no. 190 (1969).
12 Apart from one filter set in his A Photographic Study of the Brighter Plan-
Acknowledgements ets (Lowell Observatory & National Geographic, 1964, p. 101), E. C. Slipher
did not publish any of his 1949 Jupiter photographs. Scans of his negatives
The author thanks Dr John Rogers for many helpful discussions were provided by Lowell Archivist Lauren Amundson, so that the black &
white and colour composites in Figures 1–2 could be prepared by Emmanuel
on the subject of SEB Revivals in general, and 1949 in particu- Kardasis and the author using the techniques described by McKim R. J. &
lar, during the two years this paper was in preparation. Lowell Warell J., ‘New colour images from old planetary photographs’, J. Brit. As-
Observatory archivist Lauren Amundson kindly supplied scans of tron. Assoc., 123(3), 137–142 (2013).
13 Alexander A. F. O’D., Brit. Astron. Assoc., 64, 72–76 (1954)
photographic plates taken by Dr E. C. Slipher, and Emmanuel 14 McKim R. J., ‘Jupiter in 1974’, in Rogers J. H. (ed.), Jupiter, ‘1973–1977: The
Kardasis spent hours preparing the colour composites in Figure 2. Pioneer years’, Mem. Brit. Astron. Assoc., 43(1), 10–17 (1990)
Teddie Moreno of New Mexico State University Library spent 15 Rogers J. H., ‘Jupiter’s South Equatorial Belt cycle in 2009–2011: II. The SEB
Revival’, J. Brit. Astron. Assoc, 127, 264–280 (2017). For more details of his-
much time in searching for archival material relating to W. H. Haas torical SEB Revivals, see: Rogers J. H., The Giant Planet Jupiter, Cambridge
and E. J. Reese. S. Fischer provided copies of the work of C. F. M. University Press, 1995.
du Martheray, while K. Horikawa was able to provide copies of 16 IAU Circular, no. 1230 (1949 Sep 20)
17 Some pages of Frank Bateson’s 1949 diary mentioning these observations
many additional observations by S. Murayama. were kindly supplied by Audrey Waugh of the Alexander Turnbull Library,
Finally, and most importantly, this report is a tribute to those Wellington, New Zealand.
observers who upheld the Jupiter Section’s great tradition of sys- 18 Rogers J. H., The Giant Planet Jupiter, op. cit., pp. 176–177 draws atten-
tion to the differences between previously published drift rates for the central
tematic longitude measurements by simple visual means. Por- branch of the 1949 SEB Revival. McIntosh quoted the average period for 15
traits of some of them will appear in our 1950 report, which is to white spots as 9h 53m 36s,1 corresponding to a drift rate of –91°/mo. How-
be a sequel to this paper. ever, checking his published data reveals significant calculation errors, for he
should have derived a mean of 9h 54m 5s, or –70.2°/mo. Reese’s ALPO report
Address: 16 Main Street, Upper Benefield, Peterborough, Cambs., PE8 5AN quoted an average for nine spots,3 of which all but one were dark, to obtain
9h 54m 27s, or –53.6°/mo, to which McIntosh’s corrected mean is closer. As
some of their identifications were incorrect, the remaining disparity is ex-
plained. Table 3 provides a detailed comparison of the published sources.
The differences between these results, particularly for the S. branch, reflect
the mistakes in identification by McIntosh (who considered the spots always
stopped (or were turned back) at the p. side of the RSH), and Reese (who had
Notes & references plotted an otherwise plausible drift line, but in error had extended it to include
a non-Revival spot f. the RSH). From McIntosh’s data, Peek considered that
1 McIntosh R. A., ‘Disturbance in Jupiter’s South Equatorial Region’, J. Brit. one of McIntosh’s spots had a period of ca. 9h 58m,17 or Δλ2 ~ +102°/mo. Our
Astron. Assoc., 60, 247–250 (1950). It was no longer possible to access SEB(S) chart fortunately leaves no room for doubt about the correctness of

J. Br. Astron. Assoc. 132, 1, 2022 45
McKim: Jupiter in 1949 & the Revival of the South Equatorial Belt

Figures 16–18. Drawings in 1949 by E. J. Reese (152mm refl., ×200).
16. Sep 2, 01:26 UT, CM1 = 268°, CM2 = 110°; details of the SEB Revival and an NEBZ rift are shown.
17. Sep 8, 01:02 UT, CM1 = 120°, CM2 = 276°; note the STropZ dusky column f. the GRS and the NTB step-down p. the CM.
18. Sep 25, 23:56 UT, CM1 = 041°, CM2 = 060°; the SEB is highly disturbed. In the EZ, NEBs festoons reach either the EB or (at the CM) the SEB(N). (Note the illusory
apparent connection of the latter festoon with an SEBZ column.)

Figures 19–21. Drawings in 1949 by H. Wildey (Figure 19; 152mm OG (Hampstead, London)) and S. Murayama (Figure 20; 380mm OG, ×250 and Figure 21; 200mm
OG, ×180).
19. Sep 27, 20:40 UT, CM1 = 237°, CM2 = 242°; the ‘false’ GRS is shown as a conspicuous STropZ(S) shading f. the Hollow.
20. Sep 29, 09:45 UT, CM1 = 153°, CM2 = 147°; numerous SEBZ white spots and diagonal columns precede a more solid section of SEB.
21. Oct 16, 11:00 UT, CM1 = 001°, CM2 = 224°; RSH, and shadows of Europa (p.) and Ganymede (f.).

Figures 22–24. Drawings from 1949 by E. J. Reese (Figure 22; 152mm refl., ×200, with Polaroid filter in daylight) and S. Murayama (Figures 23 & 24; 200mm OG,
22. Nov 2, 22:04 UT, CM1 = 207°, CM2 = 297°; complex columns and other details in the STropZ f. the RSH.
23. Nov 11, 08:05 UT, CM1 = 034°, CM2 = 060°; four tiny NTB(S)s jet-stream spots; the SEBZ is very disturbed, with highly slanted columns; note also faint STropZ
24. Dec 4, 08:15 UT, CM1 = 067°, CM2 = 277°; SEB(N) dark spot No. 11 has reached the RSH, appearing as a dark area Nf. its centre.

46 J. Br. Astron. Assoc. 132, 1, 2022
McKim: Jupiter in 1949 & the Revival of the South Equatorial Belt
the identifications. The BAA had a considerably larger number of positional published) had observed a pair of parallel streaks within the RSH during
measurements available for the SEB features. Oct 28 – Nov 16, and from the changing position angles he inferred a rota-
19 Peek B. M., The Planet Jupiter, Faber & Faber, 1958, p. 167 tion of the Spot upon its axis in a period of 10.7 days. In 1966, Reese and
20 Phillips T. E. R., Mem. Brit. Astron. Assoc., 30(4) (1935) B. A. Smith would obtain photographic confirmation of a 9–12-day period.
21 Phillips T. E. R., ibid., 26(4) (1926) Haas later published an historical reminder (Haas W. H., J. Brit. Astron. As-
22 Peek B. M., ibid., 35(4) (1946) soc., 114, 140 (2004)).
23 Alexander A. F. O’D., J. Brit. Astron. Assoc., 64, 388 (1954). The SEB(S) 33 The early history of the S. Temperate white ovals is related by B. M. Peek in
Revival S. branch period is misprinted in the 1960 Memoir.2 The Planet Jupiter, Faber & Faber, 1958, pp. 117 & 123. His graphs show how
24 Fox W. E., Mem. Brit. Astron. Assoc., 39(1), 28 (1960) BC and DE were approaching each other in 1949, with minimum separation
25 Fox W. E., J. Brit. Astron. Assoc., 75, 35–46 (1964) in 1950. Further charts by E. J. Reese and a discussion by W. H. Haas can be
26 Rogers J. H., ‘Jupiter in 1975–76’, in Rogers J. H. (ed.), ‘Jupiter, 1973–1977: found in J. Assoc. Lunar Planet. Obs., 6(3), 35 (1952). Reese published longi-
The Pioneer years’, op. cit., 18–36 tudes up to 1961 in Sky & Telesc., 24, 70–74 (1962), and Rogers has discussed
27 Reese E. J., ‘A Possible clue to the rotation period of the solid nucleus of Jupi- their full history up to 1990 (Rogers J. H., The Giant Planet Jupiter, op. cit.,
ter’, J. Brit. Astron. Assoc., 63, 219–221 (1953) pp. 223–228).
28 Haas W. H., J. Assoc. Lunar Planet. Obs., 9(5–6), 64–67 (1955) 34 Meeus J., J. Brit. Astron. Assoc., 98, 35–37 (1987)
29 Reese E. J., Icarus, 17, 57–72 (1972). The System II longitude of Source B 35 Webb T. W., Celestial Objects for Common Telescopes, I, Dover edition, 1962,
can be calculated from the equation: λ2 = 312.3 – 0.256265 (JD–2442301). See p. 196
also Rogers J. H., The Giant Planet Jupiter, op. cit., p. 173. 36 A map of Ganymede from the 1949 ALPO work was published in J. Assoc.
30 Millar D. W., J. Brit. Astron. Assoc., 60, 239 (1950) Lunar & Planet Obs., 5(7), 1 and 9–10 (1951).
31 Shading in the STropZ was apparent throughout 1943–’44, particularly f. the 37 Peek B. M., The Planet Jupiter, op. cit., p. 63
RS when the zone was described as cream, yellow-ochre or pink by Reese, 38 Peek B. M., The Planet Jupiter, op. cit., pp. 189–190
C. F. O. Smith and Wildey: see Alexander A. F. O’D., ibid., 63, 255 & 335
32 Writing in 1949, Reese (Reese E. J., J. Assoc. Lunar Planet. Obs., 4(2), 7–9
(1949)) noted how three American observers (none of whose drawings were Received 2020 March 18; accepted 2020 September 4

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R CrA & cyclic brightness variations in
NGC 6729
Terry Evans & Grant Privett

Figure 1. The Corona Australis molecular cloud, containing the reflection nebulae NGC 6726/7 (top centre) and IC 4812 below it. The fan-like NGC 6729 is to the left
of NGC 6726 and the globular cluster NGC 6723 is to the right. (Photo by Ignacio Diaz Bobillo)

An indicative unfiltered light curve has been generated for the protostar R CrA. During the period 2018
May to 2020 November, the variability was seen to be substantial (11.5–13.1), but only weakly compliant
with the 65.7-day variability generally attributed to R CrA. The star illuminates the fan-shaped NGC 6729
nebula. Variability in the nebula was observed to begin close to R CrA and then move steadily down
the fan, fading as it progressed. Measurements of the surface brightness of the different parts of the
nebula showed an apparent relationship in the delay between brightening of R CrA and the subsequent
brightening of parts of the fan. These variations appear consistent with light echoes.

Introduction Since the introduction of affordable low-light sensors during
the 1990s, the observation of variable nebulae has become in-
‘Variable nebulae’ represent a small class of objects whose ap- creasingly popular,1 and in recent years amateurs have begun to
pearance changes significantly over timescales of years, months, obtain useful quantitative results for some nebulae.2,3
or even days. They have been known since the 1800s,1 with the NGC 6729 was discovered in 1861 by Julius Schmidt while
best known being Hubble’s Variable Nebula (NGC 2261) in using the 6.2-inch Plössl refractor at Athens Observatory.4 It was
Monoceros, Hind’s Nebula (NGC 1555) in Taurus and NGC 6729 then independently found in 1864 June by Albert Marth, working
in the southern-hemisphere constellation of Corona Australis. In with William Lassell on Malta.5 Marth noted it as a nebulous tail
recent years the list has been added to, most notably with McNeil’s from a 13th-magnitude star, lying close to the nebulae now known
Nebula (2004), and Borisov’s Nebula (2020). as NGC 6726 and NGC 6727. Schmidt noted that the nebula and
J. Br. Astron. Assoc. 132, 1, 2022 49
Evans & Privett: R CrA & cyclic brightness variations in NGC 6729
star were both variable, with the star varying over a ‘short’ tim- and refocusing after every third frame. Flats, flat darks and darks
escale. This variability was later confirmed photographically with were obtained for every data set and applied using Maxim DL. All
images captured from Hêlwan Observatory between 1911 and frames were dithered to minimise cosmic ray and pixel defects
1913 by Harold Knox-Shaw,6 who followed it for some years when stacked.
and eventually surmised that there was a relationship between the Images were captured with NGC 6729 at altitudes of between
stellar magnitude and the appearance of the nebula.7,8 30 and 60 degrees. In practice, the elevation appeared to make lit-
NGC 6729 lies at the edge of a large, dark molecular cloud in tle difference to the amount of detail apparent in the images, with
which young stars are forming and illuminating the NGC 6726/7 nights of poor transparency being the biggest cause of discarded
nebulae. The molecular cloud extends over several degrees, but images. Of the 180 nights on which data were collected, images
NGC 6729 is a small fan-like nebula roughly one-arcminute long, from 132 have been used in this study.
illuminated by the star R Corona Australis (R CrA) at its point and All data were saved as files in FITS format. Blind astromet-
T CrA near the end of the fan. NGC 6729 appears to be a mixture ric reduction was undertaken via the website,19 to
of both reflection and emission components. Within the cloud and ensure the results were of consistent accuracy and that the world
surrounding NGC 6729 lies a group of infrared sources known coordinate system (WCS) components inserted into the FITS
as the Coronet Cluster,9 of which T and R CrA are the most con- files were compatible with exploitation via the Python AstroPy
spicuous members. software library.20 To ensure the best possible accuracy from
The distance to the Coronet Cluster of young stars was found to, the ‘Advanced’ control parameter – ‘Tweak’, em-
be 150 ± 4 parsecs (pc),10 according to a study of potential Gould ployed to define the order of polynomial used within the WCS –
Belt regions. That value is very similar to the first estimated figure was increased from its default value of two, to three.
of 150 ±50pc for NGC 6729, determined by Sergei Gaposchkin
in 1936.11 However, the star R CrA itself is, according to the
Gaia DR2 catalogue, 96pc distant.12 This anomaly appears to be Data processing
caused by R CrA being a triple star, with two closely-spaced stars
of 3.0 and 2.3 solar masses at a 0.2-arcsecond separation and an In the past, the extraction of photometric data from photographic
M-type low-mass dwarf in a 45-year orbit.13 The renormalised plates of NGC 6729 was a slow and laborious process. While
unit weight error assigned by the Gaia catalogue to R CrA (Gaia good results could be achieved, the effort was rarely expended
DR2 6731199293213061632) is 19.7, which indicates a poor fit and qualitative analysis of the nebula was more common – pho-
to the single-star model used in that release,12,14 thereby justifying tometric measurement being largely reserved for R CrA itself.
considerable caution. The advent of CCDs, combined with the ready availability of
The comma-shaped Herbig–Haro object HH 100,15,16 100 sophisticated image processing software and the high-level pro-
arcseconds to the south-west of R CrA, is seen against a dark gramming language Python 3, has made the collection and pro-
nebula that is believed to attenuate the brightness of stars within cessing of data relatively simple and should, eventually, lead to
it by up to 50 magnitudes.9 While HH 100 has been reported to an increasing number of detailed amateur reports regarding vari-
be variable in the visible band, it appears to be associated with an able nebulae.
infrared source only weakly detected in visible-band imaging us- While all the data collection in this study employed only a lu-
ing large instruments.15,17 minance filter, and was thus not ideal for absolute photometry,
R CrA is a young star of approximately 1.5Myr age,13 which previous work had suggested that worthwhile quantitative re-
has been variously spectrally categorised, but is often reported sults could still be derived.2 As the data set was created using
as B5IIIe. The previously observed variability over a 65.767-day a single telescope and CCD combination, it was hoped that the
period is now attributed to the binary nature of the star.13,18 results would be more consistent than those seen previously,2 as
NGC 6729 remains a target of active research within the pro- observer-to-observer offsets were eliminated.
fessional community. Photometric solutions were derived for each image using the
Gaia DR2 data set,12 as well as bespoke Python software. Care
was taken to ensure that saturated or nearly saturated stars were
The data set not employed in the reductions, with any star containing a pixel
count above 55,000 discarded. Similarly, the 5% of stars with
Images of R CrA and its environs were collected by Terry Evans most extreme colour indices (Gaia bp-g) were discarded from
during the years 2016 to 2020. the analysis.
The images for 2018–’20 were acquired using a TMB 203 apo- To test the reproducibility of the approach, aperture photom-
chromatic refractor with an air-spaced triplet. The optical tube as- etry was obtained of three comparison stars lying close to R CrA.
sembly was mounted on a Software Bisque Paramount ME4000, These stars are not reported to be variable.
and the images collected via a Starlight Xpress Trius-694 CCD The slightly larger scatter in the 2020 values arises from
camera. Focusing was achieved using an Optec TCFS-i focuser the increased use of 60-second exposures, rather than those of
and guiding via a Starlight Xpress Lodestar and a Pentax 75mm 300 seconds. Measurement of all three stars showed a variance
SDHF guide-scope. A TruTech filter wheel with an Astronomik smaller than 0.1 magnitudes. The stars were measured as Gaia
L filter was employed. System control was via MaxIm DL. g magnitude 15.02 ± 0.06, 13.34 ± 0.07 and 14.34 ± 0.05. Their
The system was hosted at the Riverland Dingo Observatory in Gaia Catalogue values are 14.46, 13.06 and 13.80 respectively –
South Australia. suggesting, perhaps, that they are significantly reddened by the
Images were initially collected in batches of exposures, each dusty environment. They were subsequently employed for differ-
of 300s duration, with dithering occurring between each frame ential photometry.

50 J. Br. Astron. Assoc. 132, 1, 2022
Evans & Privett: R CrA & cyclic brightness variations in NGC 6729

Figure 4. The variation in brightness of R CrA dur-
Figure 2. The brightness of three comparison stars obtained ing 2020. The significance of the vertical stripes and
using Gaia g-band DR2 data as the photometric standard. markings is discussed on p.52.
The data cover the period 2018 February – 2020 October.


R CrA photometry

The light curve obtained for R CrA is presented in Figure 3. The
star varied between magnitudes 11.5 and 13.1. The variations re-
corded are fast and considerably greater in amplitude than the mi-
nor fluctuations recorded for the comparison stars, suggesting real Figure 5. The variation in brightness of R CrA as a
activity of a scale consistent with what has been noted before.13 function of phase during 2020. The data have been
folded over a 131.5-day period.
There is a suggestion of a slow overall drop in brightness during
the 2020 period, in addition to the rapid variation in amplitude of
more than a magnitude. Nebulosity brightness – qualitative results
On many of the 2018 (and some 2019) photographs, the pixel
counts within the star images indicate that CCD saturation had Qualitatively, it was apparent that, unlike McNeil’s and
occurred. These measurements were excluded from the plot. Gyulbudaghian’s nebulae, NGC 6729 retained its overall form
throughout the period observed. While details did subtly change
in brightness, the general form of the nebula was always visible –
as is found for NGC 2261.
Figure 6 shows NGC 6729 as generated by stacking the
141-image data set. It is worth remembering that, at the distance
of this nebula, each image pixel is roughly 150au wide. So, if the
nebula is orientated perpendicular to the line of sight, the time re-
quired for light to travel from R CrA to the other end, near T CrA,
is approximately 70 days.

Figure 3. The variation in brightness of R CrA over the
period 2018 February –2020 December.

It has been reported that the R CrA periodic variation of
65.767 ± 0.007 days can be made more obvious when a running
median is employed, to remove longer-term brightness variations
when viewed over two cycles (i.e., ~131.5 days).13,18 Figure 4
shows the raw, unmodified 2020 data. While it does show some
similarities to the curve produced by Sissa from American As-
sociation of Variable Star Observers (AAVSO) data, it is not well
Figure 5 shows the 2020 data folded over the 131.5-day pe-
riod. The data have not had any long-term variation filtered out.
Extending the study into 2021 might enable this correction to be Figure 6. The general appearance of NGC 6729, as derived from
the entire data set. 300s exposure. The fainter HH 100 is seen ad-
achieved. The data for 2019 were less populated but showed a jacent. The field is approximately 4×4 arcminutes across. R CrA is
similar form. the star on the left.

J. Br. Astron. Assoc. 132, 1, 2022 51
Evans & Privett: R CrA & cyclic brightness variations in NGC 6729

Figure 7. The nebula as seen over four nights in 2019: May 29, Jun 3, Jun 10 and Jun 23, respectively. The images have been similarly scaled to make changes easier to spot.

The variations observed typically involved some of the more
distinct features becoming temporarily easier to see. This gener-
ally took the form of a brightening that spread south-east from
R CrA itself, away from the star, toward the end of the nebula and
T CrA. The region of brightening moved in a manner consistent
with that of a light echo – generally reappearing at ever-increas-
ing distance from R CrA and becoming dimmer and more subtle
as time passed.
To examine this more closely, the 2020 data were visually in-
spected and the date when a new feature was seen to emerge
close to R CrA (see Figure 7) was noted. The vertical yellow Figure 8. The amplitude of the brightness variations for a
lines on Figure 4, and later in Figure 8, indicate these events. small part of NGC 6729 during 2020. The cyan line shows
The red dashes denote the dates on which it was believed that the fitted sinusoid.
R CrA would achieve peak brightness, if the 65.767-day period
was correct. of these sinusoids decreased for locations further removed from
With Gyulbudaghian’s Nebula and NGC 2261, both lobes of R CrA, reaching a limit at about 45 arcseconds distant, where the
the bipolar flow from the young star are observable in the visible variation became lost within the measurement noise.
band – if only dimly. In the case of NGC 6729, the fainter lobe Plotting the same surface brightness data while folding the val-
(assumed to be north-west of R CrA) was essentially undetect- ues on the reported 65.767-day period yields Figure 9, where the
able,21 other than very close to R CrA – presumably due to ex- dates recorded for the brightening of the nebula near R CrA ap-
treme attenuation by the molecular cloud. pear to be clustered.

Nebulosity brightness – quantitative results

To support a quantitative approach to assessing the nebulosity
brightness, an attempt was made to measure the brightness of
18 locations within NGC 6729, relative to the total brightness of
an in-scene non-variable star, measured by aperture photometry.
This method is similar to that successfully applied during a study
of Gyulbudaghian’s Nebula,2 but on this occasion, the nebula
brightness is expressed in magnitudes per arcsecond. These sur-
Figure 9. The surface brightness values for the part of
face brightness values should be seen as self-consistent, but not NGC 6729 shown in Figure 8, now folded using the period
absolutely correct. The stellar photometry provided the scaling of variability of R CrA.
necessary to generate indicative surface brightness values for
most our images. Several potential reference stars were tried, all Finally, we determined that the values of phase angle for the
giving similar results. sinusoids varied with increasing on-sky separation from R CrA.
As might be expected, the brightness estimates derived were The angle, and hence the delay between the variation of the star
most accurate for the well-exposed images. Consequently, images and the nebula, was found to increase nearly linearly until the
captured on nights of low transparency or thin cirrus were rejected. amplitude of the associated oscillation was comparable with the
Efforts were made to statistically mitigate the impact of noise on the measurement noise level, at which point the curve-fitting solu-
image sample values derived, but no image processing techniques tions became unstable.
to specifically modify pixel values were employed. Similarly, all The 2019 brightness data for the same patches of nebulosity
image sampling was undertaken on a nearest-neighbour-pixel ba- also displayed this trend and oscillations were present, but with a
sis to maximise photometric accuracy. smaller amplitude.
Upon examining the NGC 6729 surface brightness values, it To check for systematic errors, two areas of unassociated neb-
was found that many locations varied in a crudely cyclical man- ulosity within NGC 6726/7 that were distant from R CrA were
ner. An example can be seen in Figure 8, with a sinusoid fitted of examined for sinusoidal variations. These locations displayed no
65.767-day period. It was also apparent that the overall amplitude significant oscillations.

52 J. Br. Astron. Assoc. 132, 1, 2022
Evans & Privett: R CrA & cyclic brightness variations in NGC 6729
This supports the contention that these variations are directly
related to the variability of R CrA, but with their individual varia-
tions delayed due to the additional light travel time from the star.
Evidence for light echoes was found for parts of the nebula as far
as 45 light days (~7,000au) away from R CrA.
The fainter north-western lobe of NGC 6729 was only faintly
detected, very close in to R CrA.

Figure 10. The time delays of the brightness varia-
tions for parts of NGC 6729, as a function of distance
from R CrA.
The authors would like to thank Mr Andrew Wilson for his gen-
erous help in establishing the distance of R CrA and Dr Nick
Hewitt, for his support and encouragement.
Discussion They would also like to acknowledge the use of the Astrom- and Astropy software tools.
During 2020, the sinusoidal variations displayed by features with- Address (GP): West View, Knighton Rd, Broad Chalke,Wiltshire, UK, SP5 5DX.
in the nebula were relatively simple and clean, while in 2019 they []
were present, but less strong. This difference might be explained
if the environment close to R CrA contains obscuring materials
that prevent the light of R CrA from continuously, and directly,
illuminating the parts of the nebula we observed. The origin of
this may lie within the accretion disc environment immediately References
surrounding the star – as discussed by Sissa et al. (2019).13 It
1 Hewitt N., ‘Observing variable nebulae’, J. Br. Astron. Assoc., 113(6) (2003)
is possible that the parts of the nebula seen to vary cyclically in 2 Privett G. J. et al., ‘The many faces of Gyulbudaghian’s Nebula’, ibid., 129(5),
brightness during 2020 enjoyed a less cluttered line of sight to the 273–278 (2019)
star than was the case during 2019. 3 Boyd. D., ‘PV Cephei and Gyulbudaghian’s variable nebula’, Procs. SASS, 65
Considering Figure 10, it is apparent that the relationship was 4 Schmidt J. F. J., ‘Mittlere Oerter von 110 Nebeln für 1865’, Astronomische
consistent with that of a light echo from dust and gas lying in a Nachrichten, 70(22), 343 (1867)
crudely linear plane. We can speculate that this may be on the 5 Lassell W. & Marth A., ‘A catalogue of new nebulæ discovered at Malta with
the four-foot equatoreal in 1863 to 1865’, Mem. R. Astron. Soc., 36, 45 (1867)
inner edge of the cone projecting away from the pole of R CrA, 6 Knox-Shaw H., Hêlwen Observatory Bulletin, 16, 141–144 (1915)
which is being swept clean by the bipolar flow. If we assume that 7 Reynolds J. H., ‘The variable nebula in Corona Australis (NGC 6729)’, Mon.
the plane is inclined toward us relative to the plane of the sky, Not. R. Astron. Soc., 76, 645–646 (1916)
8 Knox-Shaw H., ‘Note on the variable nebula in Corona Australis’, ibid., 76,
then a simple calculation yields an inclination of 32 degrees. 646–647 (1916)
It is worth noting that Rudnitskij (1987) speculated that cycli- 9 Taylor K. N. R. & Storey J. W. V., ‘The Coronet, an obscured cluster adjacent
cal variations such as those detected herein might be seen around to R Corona Austrina’, ibid., 209, 5 (1984)
R CrA and provide structural information.22 It can also be inferred 10 Dzib S. A. et al., ‘Distances and kinematics of Gould Belt star-forming re-
gions’, Astrophys. J., 867, 151 (2018)
that they may exist around other variable nebulae but are cur- 11 Gaposchkin S. & Greenstein J. L., ‘On the distance of the variable nebula
rently unobserved. (NGC 6729) associated with R Coronae Australis’, Harvard College Observa-
tory Bulletin, 904, 8–11 (1936)
12 Brown A. G. A. et al., ‘Gaia Data Release 2. Summary of the contents and
survey properties’, Astron. Astrophys., 616, A1 (2018)
13 Sissa E. et al., ‘The origin of R CrA variability. A complex triple system host-
Conclusions ing a disk’, ibid., 630, A132 (2019)
14 Lindgren G., ‘Re-normalising the astrometric chi-square in Gaia DR2’,
GAIA-C3-TN-LU-LL-124-01, v1 (2018)
An indicative unfiltered light curve for the protostar R CrA has 15 Scarrott S.M. et al., ‘Optical polarisation studies of Herbig Haro objects – III.
been created from a sequence of observations spanning the period HH100 in Corona Australis’, Mon. Not. R. Astron. Soc., 228, 533 (1987)
16 Hartigan P. & Lada C. J., ‘CCD images of suspected Herbig-Haro objects’,
2018 May to 2020 November. The brightness range was found to Astrophys. J. Supp. Ser., 59, 383 (1985)
be between magnitude 11.5 and 13.1, unfiltered, using the Gaia 17 Kumar M. S. N. et al., ‘H2 flows in the Corona Australis cloud and in their
driving sources’, Astron. Astrophys., 533, A137 (2011)
DR2 g-band data. Rapid variations in brightness were observed, 18 Ishchenko I. M., ‘Information periodical component in the light curve of R
but the compliance with the accepted average period was not Coronae Austrinae’, Inform. Bull. Variable Stars, 865, 1, (1974)
strong – particularly during 2019. 19 Lang D. et al., ‘ Blind astrometric calibration of arbitrary as-
tronomical images’, Astron. J., 139(5) (2010)
During this period of observation all the main features of NGC 20 Robitaille T. P. et al., ‘Astropy: A community Python package for astronomy’,
6729 remained visible in well-exposed frames. Astron. Astrophys., 558, A33 (2013)
The previously reported nebula variability manifested itself 21 Ward-Thompson D. et al., ‘Evidence of discs and jets associated with R and
T CrA’, Mon. Not. R. Astron. Soc., 215, 537–544 (1985)
in the form of changes in the brightness of some features, in a 22 Rudnitskij G. M., ‘A mechanism for variability of cometary nebula’, IAU
manner consistent with light echoes. Eighteen locations within Symposia, 115, 398–400 (1987)
the nebula were examined and most were found to exhibit cy-
clical variation during 2020 that was consistent with the known
65.767-day period of R CrA. Received 2020 October 13; accepted 2020 December 5

J. Br. Astron. Assoc. 132, 1, 2022 53
Evans & Privett: R CrA & cyclic brightness variations in NGC 6729

54 J. Br. Astron. Assoc. 132, 1, 2022

80 years. The office was
in the Herschel Room and
the move has necessitated
the removal of archives
stored there to other loca-
tions. In the preparatory
work for the move, we had
to also consider items that
were on the walls or the
mantelpiece in the room,
as well as cabinets.
John Chuter On the mantelpiece was
Archivist the seal maker (embosser)
used to produce a BAA mark

A s you will be aware, the BAA
has decided, sadly, to leave
Burlington House after some
on letters, etc. I show it here
(above) together with the em-
bossed mark it makes. here (above; from the BAA Memoir ‘The BAA:
In 1911, the BAA was 21 years old. Second fifty years’), she recovered.
Its ‘coming of age’ was celebrated Her framed MBE certificate was on the wall in
by incorporation, in accordance with the Herschel Room. This picture of her (below)
the Companies (Consolidation) Act was in the 1971 October Journal.
of 1908, which confers on scientific We now award the Lydia Brown Medal for
and other societies the advantages of ‘meritorious service’ to the BAA. Without doubt,
a Limited Liability Company without she would have been a worthy recipient of the
the necessity of using the name. This medal herself.
was important because it
safeguarded the possessions
of the BAA and enabled the
officers to invest its funds.
The certificate for this was
framed and placed on the
wall, as shown (top left).
The BAA moved to Burl-
ington House from Sion Col-
lege in 1942. Lydia Brown
had joined the BAA in 1928
as Assistant Librarian and
became Assistant full-time
Secretary in 1931. From then
on, her home was used as the
BAA office, with stock and
publications held there until
she retired in 1971, after 40
years as Secretary. All the
stock etc. was then moved
to Burlington House. This
had to be delayed as she
became seriously ill in 1970
October, but as recounted

J. Br. Astron. Assoc. 132, 1, 2022 55
There are a few technical errors in
Rosetta: The remarkable story of the text, but these are not significant and
would not be noticed by most readers.
Europe’s comet explorer One of my pet irritations is misuse of
units to ‘explain’ things more clearly.
Think lengths in double-decker buses
by Peter Bond was a larger comet with or volumes in swimming pools. Also,
a stronger gravitational the use of far more significant figures
Springer, 2020 | ISBN 978-3030607197. field would lead to prob- than justified can be irritating. This
Pp 403 | £24.99 (pbk) | £19.99 (e-book) lems ten years later, when book is mercifully free of that kind of
the Philae lander bounced thing, but there are a few cases where

I am biased, but I think ESA’s Rosetta mission
to comet 67P/Churyumov–Gerasimenko is
one of the greatest achievements of the space
three times over the sur-
face due to problems with
a landing system designed
my eyebrows were raised. Bond quotes
a miss distance during one of the Earth
flybys as 2,479.523km. Accurate to a
age. To navigate the economic, political and for a smaller comet. metre. Really? Also, if you are going to
technical hurdles required to get it launched was Launch finally oc- illustrate something with an analogy, it
difficult enough, but then to navigate the space- curred on 2004 Mar 2. Bond documents the is best to make sure it is correct. The encounter
craft and its lander Philae on a ten-year journey cruise phase in fascinating detail, including velocity of Giotto with comet 1P/Halley was
to rendezvous with and orbit a four-kilometre multiple planetary and two asteroid flybys, a 68.4km/s. At this speed, Bond says you could
cometary nucleus 600 million kilometres away deep-space hibernation, and the final approach to cross the Atlantic in 11 minutes. That is not
was something really special. the comet. In 2014 August, Rosetta finally arrived long, but I think the true duration is more like a
As an engineer who worked on ground com- at 67P and started to send back stunning images. minute. These things are not that important, and
munications and a tracking system for Rosetta, Unfortunately, most of the best were not released they certainly do not detract from the quality of
I really enjoyed reading Bond’s very detailed in a timely way and Bond includes a balanced the book, but they do show that the reviewer has
account of the mission. There have been many discussion of the politics involved in the release actually read it!
books published on the cometary science aris- of data from the main OSIRIS camera. This is The final chapters of the book cover what we
ing from Rosetta, but this book is much more something that ESA does rather differently to have learned about 67P and comets in general.
concerned with the operation and management NASA, since the scientific instruments on ESA These are accurate and interesting, but where this
of the mission, and it contains plenty of detail missions are generally funded by institutions book really shines is in the day-to-day descrip-
which would be difficult to find in a digestible which expect exclusive access to the data for a tions of how a group of very clever people
form anywhere else. period to allow them to produce scientific results. managed to fly a spacecraft to a comet and land
Bond covers the initial proposals and planning While this is understandable, it did not help with on its surface. Bond has done an excellent job
for a comet sample-return mission, which started the PR of a very high-profile mission. covering that aspect and I would recommend this
just after the Giotto encounter with 1P/Halley In 2014 November, Philae was deployed book to anyone who wants to know a bit more
in 1985. He explains how the mission morphed and landed on the surface. Rosetta continued to ‘behind the scenes’ detail on this mission.
from a joint NASA/ESA sample-return project orbit the nucleus, while the comet’s activity in-
into an ESA-only comet orbiter and lander. He creased as it headed in towards perihelion. Bond Nick James
includes detailed descriptions of the scientific describes how the spacecraft had to back away
payloads on board and the spacecraft develop- from the nucleus to avoid problems due to dust Nick James is Director of the BAA Comet Section
ment leading up to the planned launch in 2003. particles blinding its star sensors. The final act on and an engineer in the space industry. He led the team
The original target comet was 46P/Wirtanen, but 2016 Sep 30 was switching off the spacecraft by responsible for the Intermediate Frequency Modem
an Ariane launch failure in 2002 led to a post- ‘landing’ it on the nucleus, 12 years after launch System, which enabled ESA to track and communicate
ponement and a change to 67P. The fact that this and 30 years after the mission was conceived. with Rosetta.

Letter: Correspondence is welcome. Please e-mail letters to, or post to
Mr Philip Jennings, 47 York Road, Malton, York, YO17 6AX, clearly marking your letter ‘for
Astronomy in a cold publication’ if you wish it to be considered for the Journal.
From Mr John Cook

In the 2021 December Journal, the ‘From the
Journal archive’ piece by John Chuter [131(6),
p.349] mentions a paper written by Mike Maun-
der, ‘Cold climate photography’, on cold weather
preparations for the 1997 total solar eclipse. It
brought back some memories! I went on that trip
and remember reading the guidance first.
As can be seen in the first photo (left), we
were all well clad while waiting for the eclipse in
Mongolia, but also notice that it was very cloudy. deep snow. The second photo (right) shows our indoors, when the higher humidity turned the
Not the best weather for eclipse viewing, regard- efforts. I cannot remember who took this picture; whole camera and tripod into a giant ice lolly!
less of the temperature. While we were all well I am the one on the far left with the woolly hat. The film inside froze solid, wrecking the majority
prepared, there were some transport problems I had further experience of cold weather in of my slides. Quite an experience.
getting there. We had flown into Krasnoyarsk in 1992, on a trip to Alaska for aurora watching.
central Russia prior to catching the train on to We had a very good view of the aurora one night John Cook
Irkutsk. While there, we had a bus trip around the at around 1–2 a.m., despite it being –20°C. My
town which involved trying to push the bus out of camera seemed to work fine until I took it back 11 Wren Ave., Perton, Wolverhampton, WV6 7TS

J. Br. Astron. Assoc. 132, 1, 2022 57
BAA Update
Commission for Dark Skies

Marlborough & Exmoor:
Starlight & night light
Bob Mizon
Coordinator, BAA Commission for In Dunster ’s well
Dark Skies equipped Tithe Barn,
Exmoor National Park
volunteers welcomed

I n 2021 October, the Commis-
sion for Dark Skies’ travelling
display visited both the Exmoor and Marlbor-
t h e C f D S d i s p l a y,
while the indefatigable
Jo Richardson (Space
ough Dark Skies Festivals, on Oct 23–25 & Detectives) and Simon
29–31 respectively. Holbeche (Bath As-
For the Exmoor event, our activities were tronomers) led excited
The 2021 Marlborough Dark Skies Festival display area, including the CfDS
based in Dunster, with both Bob Mizon and Tim junior ‘astronauts’ as stand (centre). (nPAE Precision Astro Engineering)
Wetherell (Minehead) primed to hold stargazing they launched their own
events and spread the light-pollution message. rockets and navigated
Each year, as part of the Exmoor Festival, the roving vehicles across a wonderfully recreated astronaut. The CfDS
Yarn Market Hotel in Dunster hosts groups of Mars terrain. The CfDS display attracted much stand joined many
hopeful stargazers from around the UK, and attention; this year it concentrated not just on others in the Town
Bob gives talks and leads observing from a dark the value of seeing starlight but also on the neg- Hall and our new leaf-
site at Selworthy Church, about three kilometres ative impact of modern blue-rich LED lighting let, Light Pollution &
from the north Somerset coast and to the west on biodiversity. Health – designed and
of Minehead. Sadly, clouds rolled in and most At Marlborough’s extremely well-organised written by Liam Arnull
of the event happened beneath the overcast, but festival later in the month, Bob, Kate Earl and – disappeared fast.
enthusiastic audiences in the hotel – including Steve Tonkin – all members of the Wessex Perhaps the literal
old friends and CfDS supporters from South Astronomical Society – joined colleagues from highlight of the Marl-
Wales astronomical societies in Cardiff, Barry the North Wessex AONB, Swindon Stargazers borough event oc-
Island and Swansea – made the most of the and Bath Astronomers to give talks at the ornate curred round 8 p.m. on
cosmic ambience. Town Hall and several other venues, and show the Oct 30. About 50 keen
public the wonders of the night members of the public,
sky and of our local star too. including many junior
Kate provided an unexpected hopefuls with small
treat for passing dog-walkers telescopes and one
at the town’s sports ground with a home-made as-
with her solar telescope (‘That trophotography set-up, Day 3 of the COP26 con-
little spot is the size of planet had assembled at Man- ference held in Glasgow.
Earth!’), Steve’s talks included ton: a small village (Dean Calma / IAEA)
his (light-hearted) list of the west of Marlborough
several ways in which the Uni- with starry night skies and a clear view of the
verse tries to kill us, and Bob Milky Way. Suddenly an extremely bright meteor
ran children’s Cosmic Odyssey blazed a path through the darkness, all the way
workshops on ‘What’s what in across the eastern sky. We were pointing out the
the Universe’ and being a lunar rising Pleiades at the time, so nearly everyone
was looking in the right direction – unusual for
such events.
The new CfDS leaflet, by

Liam Arnull. (Bob Mizon)

CfDS aimed in November to ensure that light
pollution, an often-ignored factor in climate
change and the decline in biodiversity, was not
forgotten during the proceedings of the COP26
conference in Glasgow. We urged our friends, the
MPs of the All-Party Parliamentary Dark Skies
Group (, @appgdarkskies),
to ensure that ministers from DEFRA and the
Local Government ministry kept it in mind while
preparing their contributions.

The BAA was a proud sponsor of the 2021 Marl-
borough Dark Skies Festival.

58 J. Br. Astron. Assoc. 132, 1, 2022

Dr Fiona Vincent (1949–2021)
F iona Vincent had a long association with the
Astronomy Group in the School of Physics
& Astronomy at the University of St Andrews,
typographical errors and ambiguities
in peer-reviewed astronomical publi-
cations, which she exposed merciless-
having studied there and contributed to public ly as a regular contributor to the ‘Here
engagement in science and academic life for and There’ column of The Observatory
most of her career. magazine.
Fiona was born on 1949 November 23 in In 1998, she delivered a series of
London, but her father’s job moved to Edinburgh lectures on Positional Astronomy as
shortly afterwards and she was brought up in a segment of the second-level under-
that city, where she went to George Watson’s graduate astronomy module in the
Ladies’ College. School of Physics & Astronomy at
She studied at the University of St Andrews, St Andrews. The URL of the superb
initially as an undergraduate after arriving in lecture notes she prepared for the
1968, and later earning her PhD in astronomy students quickly escaped into the wild
in 1980. Her subsequent career path included a on the then-new World Wide Web; it
Dr Fiona Vincent, with her husband Roger. (Photo courtesy
spell with the BBC World Service in London. soon established itself as the world’s of Jim Burke)
In 1982 she was appointed City Astronomer go-to site for information on the sub-
in Dundee and she held the post until 1994. In ject. Fiona continued to maintain these
this role, she directed a major redevelopment of pages in response to user feedback for a further whose hedges were carefully designed as a shield
Mills Observatory (then Britain’s only full-time 23 years. Today, they still provide the top hits against encroaching light pollution.
public observatory). for Google searches for ‘positional astronomy’ She was a very early member of the British
From 1996 to 2016, Fiona held an honorary or ‘spherical trigonometry’. She was delighted Sundial Society. She designed two sundials for
lectureship in the School of Physics & Astrono- to discover that she shared her name with the the Mills Observatory while she was there, as
my at St Andrews. There, with her husband and fictional Star Trek starship USS Fiona Vincent well as several others including a pair in her
colleague Roger Stapleton, she pursued a vig- NCC-8010, and that one fan site describing the garden at home. Recently, she was proofreading
orous outreach programme for primary schools ship featured a link to her web pages. for the British Sundial Society Bulletin.
throughout Fife, of which the St Andrews mobile Fiona acted as a tutor and study advisor on Having gained her radio amateur’s licence
planetarium was the centrepiece. She presented several Open University (OU) astronomy cours- while working for the BBC, Fiona maintained
some 200 shows from 1996 to 2003. Until es, including a third-year course on astrophysics the interest she shared with Roger in amateur
2012, Fiona maintained a monthly web page on that incorporated remote-observing projects with radio. Together, they put it to good use for safe-
‘What’s in the Sky’, which enjoyed a high profile robotic telescopes operated by the OU on the ty communications at car rallies and similar
among local astronomical societies affiliated to islands of Mallorca and Tenerife. Closer to home events around Scotland. Since 2007, when she
the BAA and the Scottish Astronomers’ Group. in St Andrews, she maintained active research in trained as a keep-fit teacher with the Medau
She had a sharp eye for unintentionally hilarious astrometric and photometric studies of asteroids Movement, she led a weekly exercise class for
and other small solar-system objects, from the older women in St Andrews.
home observatory that she and Roger operated
Errata in 2022 Handbook together amidst a beautifully cultivated garden, Roger Stapleton

Members are advised of the following errors
in the 2022 Handbook of the BAA, which was
enclosed with the paper edition of the 2021
October Journal:

– On p.24: ‘Superior Conjunction: –’ should
read ‘Superior Conjunction: Oct. 22’. This
information is correct in the Sky Diary
on p.5.

– Also on p.24: ‘Inferior Conjunction: Jan. 8’
should read ‘Inferior Conjunction : Jan. 9’.
This event is omitted from the Sky Diary –
it should be on p.4.

Actual UT times:
Venus inferior conjunction –
2022 Jan 9, 0:48
Venus superior conjunction –
2022 Oct 22, 21:17

Corrections to these and the errors given on
p.398 of the 2021 December Journal are also
listed at
Fiona in the planetarium at the Mills Observatory, Dundee, in c.1993. (Photo courtesy of Ken Kennedy)

J. Br. Astron. Assoc. 132, 1, 2022 59
Observers’ Forum
Variable Star Section

The Variable
Star Section
Eclipsing binaries in the beginner’s category.

CCD target list
Roger Pickard,
Assistant Director
(Director, 1999–2019)

A s outlined in an ar-
ticle on the Section
web pages (, there are two main
aims of the CCD target list:

– To encourage people who have CCD cameras,
and who have developed the ability to take
reasonable images with them, to point them
at variable stars and develop their photome-
try techniques.

– To provide some interesting targets and proj-
ects to get people involved in doing some
real science.

Charts and comparison-star sequences can be
downloaded from the American Association of
Variable Star Observers Variable Star Plotter:

Beginner’s category

The beginner’s category contains eclipsing
binaries, which show significant brightness
variations over a reasonable timescale. These
stars are guaranteed to vary. Following one or
more of these stars over a few nights allows the
beginner to test their photometric system and
see some results in a relatively short period. The
CCD mentoring scheme also puts beginners in
touch with more experienced observers. If you
would like to be allocated a mentor, contact the
Director (see p.67 for contact details).
The table at top right shows eclipsing binaries
in this category. No observations were found in
the Variable Star Section Database for EG Boo and often much more; the shortest outburst of the target is taken over a period of minutes or
and those for ER Ori were very scattered, indi- duration is two to three days. hours to look for variations in brightness.
cating they may be good stars to attempt obser- One example is V452 Cas, for which a light
vations of – perhaps after you have already had curve is shown above for the last 13 years or Other targets & projects
a successful run on another star like AC Boo, so of data.
whose light curve is given above right. Perhaps a good example of a star needing Occasionally, the Section organises campaigns
more observations. to observe particular stars, often in association
with professionals. Notifications of these are
Basic CCD data given via the BAA website, the BAAVSS-alert
Time-resolved photometry Forum and the VSS Circulars.
One field in which the amateur CCD photome- Therefore, don’t forget to join the VSS Alert
trist has made important contributions in recent Time-resolved photometry is a technique com- group at or
years is the study of dwarf novae (DNe). These monly used in the monitoring of variable stars, visit the web page at
systems have outbursts during which they in- especially cataclysmic variables. Again, the
crease in brightness by at least two magnitudes technique is relatively simple: a series of images

60 J. Br. Astron. Assoc. 132, 1, 2022
Observers’ Forum
Deep Sky Section

The Little Lion – Leo Minor
Callum Potter ▶ NGC 3344, by Ian Rothwell. Taken 2020
Director Mar 27 at 01:43 UT, from Bournemouth.
Equipment: Sky-Watcher Explorer 150P,

S ituated between Leo to the ZWO ASI 1600MM Pro-Cool and ZWO
south and Ursa Major to the EFW. 89 × 90s subs (24 × luminance, 24 ×
red, 23 × green and 17 × B).
north, the constellation Leo
Minor is a rather sparse region of the sky. There
are only three stars brighter than magnitude 4.5. The same galaxy drawn by Dale Holt on

Ancient astronomers did not recognise a con- 2020 Mar 20. Equipment: 505mm Newto-
stellation in this area, and it was Hevelius in the nian and Watec 120N+ video camera.
17th century who first marked it, in his star atlas
Firmamentum Sobiescianum sive Uranographia.
It is a rather barren area for the deep-sky observer
too, which no doubt has led to targets there being
under-observed. The constellation has no nebu-
lae, planetary nebulae or clusters of stars, but it
is well served by galaxies – many of which are Hanny’s Voorwerp is rather faint (around
interesting observing challenges, covering the magnitude 19) and IC 2497 is itself only 16th
range of galactic classifications. magnitude. Back in 2015, when I first high-
Lying in the south of the constellation, lighted this as a target, we had no observations
NGC 3344 is the brightest of the galaxies in Leo in the Section archive, but around that time Iain
Minor, at magnitude 9.9. It is a nice face-on spiral Cartwright and Grant Privett captured it. It would
with a bright core, so not too hard to find, but the be nice to see what the current generation of
spiral arms prove elusive without a large-aperture imaging technology can make of it.
telescope. It is about 6.9 × 6.4 arcminutes in size, For an imaging challenge, Leo Minor contains
so will be quite easy to image. two Shakhbazian compact groups of galaxies.
Another bright face-on spiral is NGC 3486, at These are faint and small; even in images the
mag 10.5. This is a Seyfert galaxy which has an components may still appear as faint smudges. good star atlas or charting software, you could
active nucleus, though in this case the nucleus Shakhbazian 49 is the smaller of the two groups, spend several evenings seeking them out.
is fairly quiet. at about 1.5 arcminutes, while Shakhbazian 51 Observations are always appreciated by the
NGC 2859 looks like an elliptical galaxy but is around 5 arcminutes across. Deep Sky Section, so either e-mail to deepsky@
is in fact a barred lenticular. There are no spiral There are plenty more interesting galaxies to, or upload to your Member’s
arms visible, but the bar can be detected at the locate within Leo Minor and, equipped with a Album.
ends. It would be interesting to see if any imagers
are able to capture some detail.
Another splendid spiral galaxy is NGC 3294.
Images show interesting spiral structures, with
the galaxy being about half face-on. Two super-
novae have been discovered in NGC 3294, so it
is well worth checking your images for any sign
of a ‘new star’.
NGC 3432 is a fascinating edge-on spiral
galaxy, also known as Arp 206 (from Halton
Arp’s 1966 Atlas of Peculiar Galaxies). It is
interacting with dwarf galaxy UGC 5983 and
it would be interesting to see if you can detect
the trails or filaments of the disruption, such as
those captured in the image by David Davies NGC 3432, imaged by David Davies on 2020 Mar 26 from Cambridge. An 8-inch Ritchey–Chrétien
shown here. telescope was used, with a QSI 683 mono camera and Sky-Watcher EQ8 mount. 25 × 5min luminance;
If you are collecting Arp objects, you should 10 × 5min RGB; binned 2 × 2.
also seek out Arp 270, comprising NGC 3395
and NGC 3396. This close pair of interacting
galaxies seem to be merging together and may A selection of deep-sky objects in Leo Minor
form an elliptical galaxy in the future. Object RA (h m s) Dec. (deg m s) Magnitude Size
Perhaps the most interesting object in Leo
Minor was only discovered in 2007. Hanny’s Arp 270 10 49 52.5 +32 59 20 12, 12.5 3.5ʹ
Voorwerp (‘Hanny’s Object’, pictured p.65) Hanny’s Voorwerp 09 41 03.81 +34 43 34.3 19 30ʺ
was found by Hanny van Arkel, a school teacher NGC 2859 09 24 18.54 +34 30 48.16 11.35 4ʹ
NGC 3294 10 36 16.25 +37 19 29.02 11.7 2.2 × 1ʹ
in the Netherlands, when looking at images as NGC 3344 10 43 31.150 +24 55 19.99 9.9 6.9×6.4ʹ
part of the Galaxy Zoo citizen-science project. NGC 3432 10 52 31.132 +36 37 07.60 11.7 6.8×1.5ʹ
It seemed to appear as a ‘blob’ in the foreground NGC 3486 11 00 23.946 +28 58 29.35 10.5 6.3×4.5ʹ
of the galaxy IC 2497. It has been classified as Shk 49 10 15 15.0 +38 56 06 1.5ʹ
a quasar ionisation echo, but what illuminates it Shk 51 10 30 33.90 +39 12 32.5 5ʹ
is rather unclear.

J. Br. Astron. Assoc. 132, 1, 2022 61

BAA Summer Meeting, 2021 June 26
held on the Zoom online conferencing platform & streamed on the BAA YouTube channel
Alan Lorrain, President

Bill Tarver, Hazel Collett & Prof Jeremy
Shears, Secretaries

Alan Dowdell
Meetings Recorder

T his meeting was held in two
sessions on Saturday, 2021
Jun 26; the first was at 11 a.m.
and the second at 2.30 p.m. It was held using the
Zoom conferencing platform and livestreamed
via the Association’s YouTube channel.
The meeting was opened by the President,
Alan Lorrain, who noted that the meeting was
originally arranged to be held face-to-face in
Elgin, Scotland, but had been replaced with a
webinar due to continued restrictions caused by
the pandemic.
He then introduced the morning speaker,
Dr Nicolas Peretto from Cardiff University. In this artist’s impression of the LSPM J0207+3331 white-dwarf system, an asteroid (lower left) is dis-
integrated by its parent star. Infrared observations suggest that the star is surrounded by two rings of
material accreted as infalling bodies are ‘eaten’. (NASA’s Goddard Space Flight Center/Scott Wiessinger)
‘The earliest stages of star cluster
In answering a few questions, Dr Peretto red-giant stage until, once fuel for nucleosyn-
To understand how a star is formed, we need to clarified that for the hydrogen to form molecules, thesis is exhausted, the core finally collapses
understand cluster formation, since most stars dust grains are required. A question was asked and a planetary nebula is formed by ejection of
form in clusters. Looking, say, at the example about the influence of a supernova in starting the star’s outer layers. The white dwarf which
of the galaxy M51, it is seen that the locations the collapse of a cloud. He thought that if the remains is about the size of the Earth, but with
of young star clusters follow the dark lanes in supernova was too close, it would break the most of the mass of the original star.
the arms, which are composed of cold dust. It cloud up, but there may be some cases where The planets orbiting around the star may or
is the same in our Milky Way: these cold dust some shielding effects may help prevent this. In may not survive this evolutionary process, the
regions are the areas where hydrogen gas can answer to a further query, he noted that electro- inner ones being absorbed into the star as it
form into molecules. static forces did not affect the collapse process. becomes a red giant, while ones more distant
By making observations using CO as a tracer Magnetic fields can enhance the process, but they move outward when the planetary nebula phase
gas for molecular hydrogen, we can map out could also prevent it. is reached. Some of the smaller bodies, such as
the density of the latter. Star formation is found Andrew Wilson, who managed the webinar comets and asteroids, are flung out of the system;
to be closely related to the densest parts of the and took the questions, then thanked the speaker however, some are flung inwards so that they
molecular clouds. Parsec-sized high-density and the first session was closed. go crashing into the star or are torn apart by
features are called clumps, and these have about The meeting was reopened at 2.30 p.m. and gravitational forces when in proximity to it. This
the same dimensions as a young cluster – for Mr Lorrain welcomed back members. He then in- white-dwarf star is a solid body of some 6,000km
example, the Pleiades cluster is about three troduced the next speaker, Dr Amy Bonsor, who in diameter with a thin hydrogen atmosphere
parsecs in scale. is a Royal Society Dorothy Hodgkin fellow at the about 50km deep. Any bodies falling into this
What makes these clumps of gas and dust Institute of Astronomy, University of Cambridge. atmosphere are revealed either using transits or
collapse into existence from the surrounding gas from spectra.
cloud? Gravity ‘tries’ to make them collapse, but The main elements of Earth are Fe, O, Si
turbulence in the cloud acts to tear them apart and ‘Planet-eating white dwarfs: the fate of and Mg; those of, say, a comet are similar but
thus prevent star formation. Describing research planetary systems’ in different relative amounts (and with carbon
that has not yet been published, the speaker ex- being an important addition). So, by looking at
plained how a ratio of turbulent to gravitational Dr Bonsor commenced by saying that this talk the white dwarf’s spectrum, we can tell what
energies of the clumps (a function of their radius) would be about the work she has been undertak- type of body has been broken up and determine
can be calculated. From these calculations, the ing at Cambridge. We are learning very quickly its chemical make-up.
different densities of molecular hydrogen are about planetary systems, which we now expect The Earth has a large iron core, but is this com-
mapped using tracers. The gas diazenylium to accompany almost every star. We have found mon among exoplanets? From these white-dwarf
(N2H+) is used as a tracer in the denser regions. around 5,000 exoplanets, the first to be con- observations, cases of iron cores being ‘eaten’ by
Dr Peretto showed various plots of mass and firmed – 51 Pegasi b – being discovered in 1995. the star have been inferred.
velocity dispersion hence derived as a function of Interestingly, however, a spectrum obtained over We can also use observations to derive
radius in these clumps. By combining the results 100 years ago of the white dwarf known as van information about the mass of the body being
obtained for 27 clouds, it can clearly be seen that Maanen’s Star showed a then-unrecognised broken up, while its diameter may be obtained
there is a discontinuity that allows for clumps and planetary system. from modelling.
thus clusters to form from an otherwise stable White dwarfs are the end-of-life result of an Mr Wilson thanked Dr Bonsor and the meeting
molecular cloud. average star like our Sun, which goes through a was closed.

62 J. Br. Astron. Assoc. 132, 1, 2022

BAA Autumn Meeting, 2021 September 4
held on the Zoom online conferencing platform & streamed
on the BAA YouTube channel
Alan Lorrain, President The light may be polarised by scattering off
electrons (Thomson scattering) or dust (which
Bill Tarver, Hazel Collett & Prof Jeremy is wavelength dependent). Thomson scattering
Shears, Secretaries results in polarisations of photons in various
directions dependent on the angle of the scat-

T his Saturday meeting was held as a webi- tering; the asymmetric distribution of a bow
nar and was introduced at 11 a.m. by the shock ensures this polarisation is not cancelled
President, Alan Lorrain. He said that this was out and is observable. Various possible types of
originally going to be an all-day face-to-face polarisation (e.g. linear or circular) are mathe-
meeting in Leeds, but of course this sadly could matically described by the Stokes parameters of
not happen due to the ongoing pandemic. polarisation. The use of the Monte Carlo radia-
The speaker would be Dr Manisha Shrestha, tion transfer of light from the source, which goes
who is a Postdoctoral Fellow in the Astrophysics into the bow shock and then on to the observer,
Research Institute at Liverpool John Moores was also explained.
University. Polarisation maps have shown structural
details and provided information on the tempera-
ture of the medium. When looking at polarisation
‘Stellar-wind bow shock: a laboratory due to dust scattering this is less straightforward
to study stellar wind & the interstellar than for Thomson scattering, as it depends on the
medium’ incidence angle and different
dust types. Simulations have
Dr Shrestha started by looking been undertaken in different
at stellar evolution. Stars under wavelengths as well. This was
eight solar masses evolve through illustrated by various modelled
main-sequence and red-giant stag- results and comparisons with
es, eventually becoming a white real observations.
dwarf. Stars above that mass limit In one example, applying
go through a red supergiant stage, such modelling to a bow shock
but following the termination of object near our galaxy’s centre,
nucleosynthesis of progressive- IRS8, enabled Dr Shrestha and
ly heavier elements, a superno- Dr Manisha Shrestha. (As- her colleagues to constrain
va occurs. Although this is well trophysics Research Institute) optical depth. From this, and
understood, we do not have an the inclination angle, they cal-
explanation for why there are different types culated a number density of 105 cm–3 for the
of supernovae, and how the mass of the star interstellar medium in this region. Doing this for
determines which type occurs. other objects shows that very good agreement
Stellar winds from massive stars have ve- can be obtained with values obtained through A young star at around 20 solar masses, zeta Ophi-
locities that are in the order of 20–2,000km/s, other means. uchi (central) hurtles through the surrounding in-
generated by mass loss from the star. The in- In the future, more hydrodynamic modelling terstellar medium at 24km/s, producing the bow
teractions of these streams of particles with the is needed, as well as observations of more bow shock in this infrared image obtained by NASA’s
interstellar medium can cause a bow shock to be shocks. The latter is currently being undertaken Spitzer space telescope. (NASA/JPL-Caltech)
produced at the interface between the two. The using the Liverpool Telescope.
winds are, relative to the local interstellar medi- Dr Shrestha concluded that observing bow
um, supersonic in velocity and this differential shocks is a good method to investigate the
is responsible for the bow shock: an aspheric interstellar medium and stellar winds, with the Papers accepted by Council on
region of local density. polarisation signatures allowing us to determine 2021 July 18 & September 4
Mass loss rates of massive stars, determined dust types and temperatures.
through observations of their bow shocks, are in After a few questions, Andrew Wilson One paper, proposed by Prof Jeremy Shears,
good accord with theoretical models. The bow thanked Dr Shrestha for her detailed, informa- Papers Secretary, was accepted virtually on
shock of the rapidly evolving star Betelgeuse tive talk and the meeting was closed. 2021 July 18 by the BAA Council for publi-
shows it has only very recently entered the cation in the Journal:
red-supergiant stage. Observations now have Alan Dowdell, Meetings Recorder
been obtained that show many massive stars Saturn during the 2009/2010 apparition, by Mike
have these bow shocks, which not only reveal Foulkes.
properties of the stellar system, but also of the
surrounding interstellar medium. A further paper was proposed for publication
Images of bow shocks that have been ob- by Prof Shears at the 2021 September 4 Coun-
tained in polarised light show the geometry cil Meeting and was duly accepted:
of the shock and provide information on the Neptune in 2016–2017, by John Sussenbach.
composition: specifically, the dust-to-gas ratio.
The speaker continued by explaining in depth A bow shock accompanies the star LL Orionis, in Philip Jennings, Editor
the cause and the effects of this polarisation. the Orion Nebula. (NASA)

J. Br. Astron. Assoc. 132, 1, 2022 63
Sky Notes
by Brian Mills

by Nick Hewitt 2022 February & March
(Written for 22:00 UT in the NGC 3628 with tidal tail, imaged on 2021 Apr 9. This galaxy is one of three (the others being M65 and
UK on March 1.) M66) that are together known as the Leo Triplet. Equipment: C14 Edge HD, Fornax 52 mount, HyperStar
system, ƒ/1.9; ASI 294 MC PRO. (Luigi Morrone)

F ebruary be-
gins with
Orion astride
explosion. Currently, around 30,000 years ago
is favourite (Figure 4).
Following the zodiac east is Cancer, the crab.
the meridian at mid-evening and Nestled between Gemini and Leo, and consid-
he is our invaluable seasonal guide. erably less ostentatious than the flashy twins,
His belt stars are unmistakable Cancer still boasts two superb and contrasting
and extrapolating a line south, we clusters, and a most extraordinary object: the
encounter the hunting hound Canis twin black hole OJ 287. The clusters are the
Major, with scintillating Sirius famous Praesepe, also known as the Beehive
too obvious to miss. This larger (Messier 44), and Messier 67, an ancient open
dog is in pursuit of the somewhat cluster. Praesepe is large and relatively close at
overlooked hare, Lepus, nestling 610 light-years distant, containing around 200
directly beneath Orion. There are stars spanning 1.2 degrees, so rich-field tele-
so many marvels in the winter sky scopes or large binoculars give the best views.
that Lepus does not always get From a dark site it is an easy naked-eye cluster.
much attention, but there are a few (Figure 5).
Figure 2. Messier 79 and comet C/2014
sights worthy of a detour. Lovejoy on 2014 Dec 29. iTelescope 0.61m
While Praesepe is a mature cluster at 600
Perhaps the best known of these PlaneWave; 1 × 300s exposure. (Alan Tough) million years old, Messier 67, around eight de-
is Hind’s Crimson Star, R Leporis grees to its south-east, is a geriatric. Less than
(Figure 1). It is a carbon star and half the size and three magnitudes fainter than
one of the ruddiest variables in Nebula, the Christmas Tree Cluster with Praesepe, it is nevertheless rich and rewarding.
the heavens, particularly when at Figure 1. Hind’s its associated Cone Nebula, and Hubble’s One of the oldest open clusters known, it may
minimum which occurs every 14.5 Crimson Star, R Lep- Variable Nebula (NGC 2261), are all be 3.5 billion years old and its stars are well
months. It should now be reason- oris. (Damian Peach) popular favourites. evolved, with unusually high numbers of red
ably bright as it is around its max- To Orion’s north-east, Gemini is now giants and white dwarfs. It owes its longevity
imum, at which time it is typically magnitude 7 at its most magnificent and is the most northern both to its richness and its position well away
but can be brighter as in autumn 2020. Find it of the zodiacal constellations. One of the best from the galactic plane, reducing gravitational
by taking a line from delta Orionis (Mintaka) open clusters in the sky is the easy binocular disruption. (See 130(1), p.60.)
through Rigel; R Lep will be just short of this treat Messier 35, lying just north-west of the na- Not far from Praesepe lies OJ 287, a favourite
second distance. ked-eye pair representing Castor’s left foot: Tejat amongst observers of active galactic nuclei and
In addition, no Messier survey can be com- and Propus. Nestling between these two orange one of the best-studied by professionals. The
plete without the globular cluster Messier 79 stars is one of the rare supernova remnants acces- current model suggests a supermassive black
(Figure 2). It is low at –24 degrees declination, sible by amateurs – IC 443, the Jellyfish Nebula. hole of some 18 billion solar masses, in a dance
but it is small and bright, so not difficult if the It is the remains of a supernova that occurred in with a smaller black hole of a mere 100 million
horizon is not too cluttered. Alpha (Arneb) and the distant past, although in the literature there solar masses. Surrounding the larger black hole is
beta (Nihal) Leporis point to it, and binoculars is a wide range of estimates for the time of the an accretion disc estimated to be 100 light-weeks
or a finder should locate it at
magnitude 8.5. It is small
in apparent diameter
(8.7 arcminutes), as
it is quite distant at
42,000 light-years.
A little further
north in the constel-
lation is IC 418, a
planetary nebula that
requires moder-
Figure 3. The Spirograph
Nebula, IC 418. HST image
ate magnification.
released in 2000. (NASA) Known as the Spi-
rograph Nebula, it is
fairly bright at magnitude 9.6, but is a small oval
of 11 arcseconds. The Hubble Space Telescope
has revealed exquisite detail that is beyond the
amateur (Figure 3).
Above the panting pooch sits Monoceros
the unicorn, occupying the triangle formed
by Betelgeuse and Procyon in the north and
Sirius in the south. There are no bright stars in
the fabled constellation, but there are deep-sky Figure 4. The Jellyfish Nebula, IC 443, at the foot of Castor. 2016 Nov 11. Takahashi FSQ106ED, Mesu-mount
treats aplenty, especially for imagers; the Rosette and Starlight Xpress full-frame camera. 10 hours exposure. Les Granges, France. (George Sallit)

64 J. Br. Astron. Assoc. 132, 1, 2022
Sky Notes
IC 2497, it is perhaps one of the most peculiar
objects in the heavens (see Figure 7).
Phases of the Moon
Leo itself is a superb constellation, packed full 2022 February & March
of accessible galaxies and heralding the galaxy
feast on offer from February through to May. By
late March, Virgo is well up in the east, with the New First quarter Full Last quarter
bowl-shaped ‘Realm of the Nebulae’ brimming
with galaxies that spill into Leo to the west, Feb 1 Feb 8 Feb 16 Feb 23
Mar 2 Mar 10 Mar 18 Mar 25
Coma and Canes Venatici to the north and Ursa Apr 1
Major overhead.

Neptune slips into the evening gloaming early in
Solar system February, before conjunction on Mar 13.
Of the asteroids and dwarf planets, (1) Ceres
There are no solar or lunar eclipses in 2022 Feb- remains in Taurus, between the Hyades and
Figure 5. The Moon, Venus and Praesepe on 2020 ruary or March. The vernal equinox on Mar 20 Pleiades. (2) Pallas and (3) Juno are both in
Sep 14, at 04:44 UT. Canon 6D and 135mm ƒ/4 lens. is followed by British Summer Time beginning Aquarius but lost in the evening glow.
Salcombe Regis, East Devon. (David Strange) on Mar 27. The Sun has shown signs of activity
through autumn of 2021, so it is anticipated that
in diameter, through this will increase. As the days draw out, oppor- Comets
which the ‘tiddler’ tunities for observation improve.
plunges during its Turning to the planets, this is a season for There are no bright comets anticipated at the time
12-year orbit. The optimistic early birds rather than evening owls, of writing, but there are fainter ones available and
pair are at a distance as most of the planets are either showing poorly favourably placed.
of 3.5 billion light- in the morning or are completely invisible. C/2019 L3 (ATLAS) is in Gemini although
years: possibly the Mercury has a morning showing with greatest not very bright. It is at perihelion on Jan 9
furthest objects that western elongation on Feb 16, but it is extremely and likely to be fading by February, with a
most amateurs can low and thereafter difficult. Superior conjunction predicted magnitude of around 13. C/2017 K2
image (Figure 6). Figure 6. OJ 287 flares to occurs on Apr 2. (PanSTARRS) will be at a reasonable altitude
South of Cancer magnitude 13.5 on 2016 Venus also is a dawn beacon, a brilliant-al- in Aquila on March mornings, but still faint.
is the head of Hydra, Feb 10. Comparison stars beit-low ‘morning star’ in northern Sagittarius The best comet during this period is likely to
the sinuous serpent are shown without decimal reaching western elongation on Mar 20 when be 19P/Borrelly, as it sweeps east from Pisces to
that will eventually points. 150mm APM at ƒ/7 just 10 degrees above the horizon. As the phase Perseus through February and March during the
take us from winter and SXV-H9; 12 × 2min. increases, the apparent diameter decreases, but convenient mid-evening. It reaches perihelion on
into spring. Slithering (Nick Hewitt) the magnitude remains around –4.5. Feb 1 so may be the brightest available comet,
east, Hydra passes Mars joins the early morning throng and lies possibly achieving 9th magnitude although the
under Sextans, then Crater, curling underneath below Venus, but is much fainter (+1.3) and so predicted magnitude is fainter. 29P/Schwass-
Corvus and Virgo to terminate beneath Libra. an unrewarding target for now. mann–Wachmann remains high in Taurus. It
Despite its extreme length, there are few trea- Jupiter is visible in the early evenings of Feb- is likely to be faint, although it has been rather
sures on show, the best fare being the fine open ruary, but very low in twilight. It is in conjunction exciting with its flare-ups through autumn 2021.
cluster Messier 48 near Hydra’s head, the co- with the Sun on Mar 5.
lourful planetary nebula NGC 3242 (the Ghost Saturn reaches conjunction on Feb 4 and is
of Jupiter) to the west of Crater, the globular slow to emerge into the morning sky. Venus, Meteors
cluster Messier 68 south of Corvus and the fine Mars and Saturn gather in a very tight group in
southerly galaxy Messier 83, which lies almost the predawn sky at the end of March and early The Delta Leonids have a maximum on Feb 25.
20 degrees south of Spica. April, but will be much better placed from more Derived from 55P/Tempel–Tuttle, this is not a
North of Cancer is also bare scrubland, where southerly latitudes. rich shower, but the Moon should not interfere
hides the elusive Lynx. This rare feline is rep- Uranus remains well placed in Aries during this year. The Pi Virginids, also weak, will be
resented by a string of faint stars running from February but thereafter becomes more difficult. free of the Moon in early March.
third-magnitude alpha Lyncis north-west towards
northern Auriga. It splits Ursa Major from the
charioteer. The best deep-sky object within is the Lunar occultations
‘Intergalactic Tramp’, NGC 2419, a very distant Date Time (UT) Star Mag. Ph. % Illum.
globular. (See 130(1), p.61.)
Another underwhelming and hence over- Feb 10* 1:44.9 56 Tau 5.3 DD +63
looked constellation is the little lion, Leo Minor Feb 11 0:48.3 103 Tau 5.5 DD +72
(see p.61). Added to the list of star patterns by Feb 21 4:6.4 82 Vir 5.0 RD –79
Hevelius in 1687, it is not clear of what he was Feb 24 4:09 Rho Oph A 5.0 RD –47
Feb 24† 4:08 Rho Oph B 5.7 RD –47
thinking. Perhaps he wished to add a buffer Mar 21 4:45.3 Lambda Vir 4.5 RD –90
between enormous Ursa Major to the north and
splendid Leo to the south, but surely extending Selected occultations of stars brighter than magnitude 5.5 as
Leo’s mane would have made more sense. seen from Greenwich. DB = star disappears at bright limb;
Possibly because of this invention, Leo Minor RD = star reappears at dark limb. Please see the Handbook of
the BAA for more details and for occultations of fainter stars.
has no alpha star, although 46 Leo Minoris, or
Notes: * Very low. † Low.
Praecipua, is brighter than beta at magnitude
3.8. The IAU agreed to this inclusion a century Grazing occultations
ago, in 1922, so we have to live with it. Many
faint galaxies abound, and there is one exotic Date Time (UT) Star Mag. Notes
phenomenon: Hanny’s Voorwerp (detailed on Figure 7. Hanny’s Voorwerp, near IC 2497. Feb 4 19:44 SAO128648 7.4 N. Scotland
p.61). A green splodge near the spiral galaxy HST and WFC3. (Courtesy NASA and ESA)

J. Br. Astron. Assoc. 132, 1, 2022 65
Notice Board
Music, University of Leeds, Leeds, LS2 9JT. The
Meetings Joining BAA webinars programme will be announced soon. For further
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Joining instructions for each event are on the
Entries for this diary should be sent to the BAA website at All Postponed event: The UK Exoplanet Communi-
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66 J. Br. Astron. Assoc. 132, 1, 2022
Trustees and Council Session 2021–2022
The Board of Trustees
Variable Star: Prof Jeremy Shears, ‘Pemberton’, School Lane, Bunbury,
President: Dr David Arditti, 94 Stag Lane, Edgware, Middx. HA8 5LW. Tarporley, Cheshire CW6 9NR. Tel. 07795 223869. E-mail: bunburyob-
Tel. 02082 043999. E-mail: president
Vice-President (ex officio): Alan Lorrain Deep Sky: Callum Potter, The Cottage, Bredon’s Hardwick, Tewkes-
Treasurer: Dr Geoffrey King, 29 Norfolk Road, Turvey, Beds. MK43 bury, GL20 7EE. Tel. 01684 773256 (evenings). E-mail: deepsky @
8DU. Tel. 01234 888935. E-mail:
Secretary (Business): Bill Tarver, 3 Brook Close, Wokingham, Berks. Radio Astronomy: John Cook, 11 Wren Ave., Perton, Wolverhampton
RG41 1ND. Tel. 07831 789435. E-mail: WV6 7TS. Tel. 01902 747616. E-mail:

Other elected members of the Board: Equipment & Techniques: Dr David Arditti, 94 Stag Lane, Edgware,
Middx. HA8 5LW. Tel. 02082 043999. E-mail:
Ann Davies, John Chuter, Janice McClean, Dr Richard McKim,
Lyn Smith Computing: Steve Harvey, 3 North Holmes Close, Horsham, W. Sussex
RH12 4HB. Tel. 01403 269037. E-mail:
Historical: Mike Frost, 70 Arbour Close, Bilton, Rugby, Warwicks. CV22
The Council 6EH. Tel. 01788 814643. E-mail:
Secretary (Papers): Prof Jeremy Shears, ‘Pemberton’, School Lane,
Bunbury, Tarporley, Cheshire CW6 9NR. Tel. 07795 223869. E-mail: Postholders
Journal Editor: Philip Jennings, 47 York Road, Malton, York YO17
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ciation, Burlington House, Piccadilly, London W1J 0DU. Tel. 07944
751277. E-mail: Public Relations Officer: Dr John Mason, 51 Orchard Way, Barnham,
West Sussex PO22 0HX. Tel. 01243 554331. E-mail: docjohn @
Other elected members of Council:
Marie-Louise Archer, Alexandra Hart, Tim Parsons Archivists: Dr Richard McKim, Cherry Tree Cottage, 16 Upper Main
St., Upper Benefield, PE8 5AN. Tel. 01832 205387. E-mail: richard-
Directors of Sections; & John Chuter, Ivy Cottage, Ham Hill, High
Ham, Nr Langport, Somerset TA10 9BD. Tel. 01458 250130. E-mail:
Solar: Lyn Smith, 1 Montboy Steading, Careston, Brechin, Angus, Scot-
land DD9 6RX. Tel. 01356 630218. E-mail:
Commission for Dark Skies: Bob Mizon, 38 The Vineries, Colehill,
Lunar (Acting Director): Dr Tony Cook, Department of Physics, Aberys-
twyth University, Penglais Campus, Aberystwyth, Ceredigion, Wales, Wimborne, Dorset BH21 2PX. Tel. 01202 887084. E-mail: bob.
SY23 3FL. Tel. 07985 055681. E-mail:

Mercury & Venus: Dr Paul Abel, School of Physics & Astronomy, Uni- UK Nova/Supernova Patrol: Guy Hurst, 16 Westminster Close, Kempshott
versity of Leicester, University Road, Leicester, LE1 7RH. E-mail: Rise, Basingstoke, Hants. RG22 4PP. Tel. 01256 471074. E-mail:
Mars: Dr Richard McKim, Cherry Tree Cottage, 16 Upper Main St., Up- New members coordinator: Peter Carson, 85 Whitehouse Road, Leigh
per Benefield, PE8 5AN. Tel. 01832 205387. E-mail: richardmckim@ on Sea, Essex SS9 5ST. Tel. 07875 220036. E-mail: membership@
Asteroids & Remote Planets: Dr Richard Miles, Grange Cottage, Golden Website queries:
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Jupiter: Dr John Rogers, ‘Capella’, Mill Hill, Weston Colville, Cambs.
CB21 5NY. Tel. 01223 290221. E-mail: Events coordinator: Ms Janice McClean, c/o British Astronomical Asso-
Saturn, Uranus & Neptune: Mike Foulkes, 2 The Hawthorns, Henlow, ciation, Burlington House, Piccadilly, London W1J 0DU. Tel. 07818
Bedfordshire SG16 6BW. Tel. 01462 810985. E-mail: mike.foulkes 030786. E-mail:
Comet: Nick James, 11 Tavistock Rd., Chelmsford, Essex CM1 6JL. Tel.
01245 354366. E-mail: BAA Office: Burlington House, Piccadilly, London W1J 0DU.
Meteor: Dr John Mason, 51 Orchard Way, Barnham, W. Sussex PO22 Tel. 0207 734 4145. E-mail:
0HX. Tel. 01243 554331. E-mail:
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Cornhill, Banff, Aberdeen AB45 2HJ. Tel. 01466 771371. E-mail:

J. Br. Astron. Assoc. 132, 1, 2022 67
Journal of the British Astronomical Association

Index to Volume 131 (2021)
Prepared by Hazel McGee

The Subject Index references items under general headings. Where a contribution covers two or more clearly defined subjects, each is separately
referenced, but otherwise sub-headings within the same topic are not included. Book reviews are indexed as such, but their subjects are not further
cross-indexed. The Author Index details all named contributions, including talks at Ordinary Meetings, but not questions from the floor.

Abbreviations: ill.= illustration news= in Notes and News, BAA Update or Observers’ Forum
ltr.= letter to the Editor obit.= obituary
mtg.= meeting contribution rvw.= publication or equipment review

Pagination: (1) 1–64, (2) 65–128, (3) 129–196, (4) 197–264, (5) 265–332, (6) 333–400

Subject index − An evening with the Sinden brothers (ltr.), 181 − Using Gaia DR2 data to determine the distanc-
− Graham Salmon (1932–2021) (news), 133 es of young star clusters and their distribution
Announcements and BAA Notices − Memories of Dr Edward Yeadon (ltr.), 57 in the galactic plane, 97
− Answers to the 2020 Christmas Quiz (news), 16 − Reginald Lawson Waterfield (1900–1986), Eclipses and occultations
– The BAA at Burlington House: The end of an eclipse chaser & comet photographer extraor- − The annular solar eclipse of 2021 June 10
era (news), 336 dinaire: Part I, 158 (news), 68
− The BAA Awards for 2020 (news), 3 − Reginald Lawson Waterfield (1900–1986), − Memories of Venus occulting Regulus in 1959
– BAA Christmas Quiz for 2021 (news), 338 eclipse chaser & comet photographer extraor- (ltr.), 323
– BAA Instruments for sale (news), 268 dinaire: Part II: 1939–’86, 236 − Observing asteroidal occultations from cislu-
− From the President (news), 3, 67, 131, 199, − Peter Clark (1938−2021) (news), 194 nar space (ltr.), 251
267, 335 − Prof Roger Griffin (1935–2021) (news), 141 − Partial solar eclipse, 2021 June 10 (ills.),
− Index to Journal, vol. 130 (2020), facing 32 − Solar observer Monty Leventhal receives 199
− New Honorary Members, 209 BAA Ridley Grant (news), 205 − A Patagonian eclipse (ill.), 1; (news), 6
− New members elected, 53, 117, 183, 252, 318, − Three Girton astronomers (news), 141 − Some merit in observing asteroidal occulta-
368 Comets tions from the ground (ltr.), 323
− Nominations for the Ballot for Council & − MISSION 29P: A review of progress & a re- – Using a lunar eclipse to measure the diameter
Board of Trustees, 53, 116 cent strong outburst of comet 29P/ Schwas- of the Earth’s shadow (news), 320
− Nominations invited for the eighth Sir Patrick smann–Wachmann (news), 70 − A well-observed double star occultation –
Moore Prize (news), 201 − The brighter comets of 2017, 27 SAO 93840 (HO 328) (news), 73
− Papers accepted by Council for publication in − Comet prospects for 2022 (news), 392 Extrasolar planets
the Journal: 59, 123, 191, 257, 259, 327, 395 Commission for Dark Skies − Fantastic planets and how to find them (mtg.),
− President’s Review of the Year, 2019−2020 − Award for lighting scheme at Wimborne First 256
(mtg.), 188 School (news), 52 – Microlensing search for exoplanets – a new
– Recovery of astronomical instruments (news), − CfDS braves the elements (news), 252 pro-am project (news), 340
267 – Lights & lies (news), 271 – Observing exoplanets with the MicroObser-
– Report of the Council, Trustees’ Report and – Light pollution, biodiversity & climate change vatory: 43 new transit lightcurves of the hot
financial results for 2020−2021, 299 (news), 342 Jupiter HAT-P-32b, 359
− Winners of the 2020 Christmas Quiz (news), 68 Cosmology − Of plants & planets: speculating on the flora
− Your vote for the BAA Trustees & Council − How the Universe will end (mtg.), 122 of Kepler-186f (ltr.), 385
(news), 200 − Stumbling in the dark: the search for the Uni- Galaxies
Asteroids verse’s missing mass (mtg.), 123 − Lighthouses in the Universe: the tale of ultra-
− Success for two sample-return missions to as- Deep sky luminous infrared galaxies (mtg.), 326
teroids (news), 5 − Ancient Light : Imaging a quasar without a – Quasars, black holes and the future of the
Aurora & noctilucent cloud telescope (news), 120 Milky Way (mtg.), 394
− Aurora & noctilucent cloud activity (news), 8, − The Beehive Cluster, Messier 44 (ill.), 65 – Quasar unification via disc winds: from phe-
69, 136, 200, 275, 347 − Europlanet bid success for variable nebulae nomenology to (astro)physics (mtg.), 394
− Aurora, STEVE and noctilucent clouds observers (news), 78 History
(mtg.), 59 − Nebulae, clusters & variable stars (news), 119 − Arthur Stanley Williams’ lens rediscovered
− Noctilucent cloud over Britain & Western Eu- – NGC 2683 – a glorious galaxy in Lynx (news), (ltr.), 57
rope, 2019, 171 391 − Centenaries for 2022 (news), 384
− The return of noctilucent cloud (ill.), 129 − NGC 6751 – an overlooked planetary nebula − Early history of the shadow bands in Aris-
Biographical in Aquila (news), 254 tarchus (ltr.), 386
– The 2021 George Alcock Memorial Lecture: − Open clusters for the summer months (news), – Five thousand years of Jupiter–Saturn con-
George Alcock goes to Antarctica, 278 185 junctions, 369
− Arthur Stanley Williams’ lens rediscovered – Our friends in the north (news), 321 − From the BAA archives (news), 51, 114, 183,
(ltr.), 57 – Pickering’s Triangle (ill.), 335 250, 324, 388
− The artwork of Ron Livesey (ltr.), 251 − Planetary nebulae in Gemini (news), 55 − From the BAA bookshelf (news):
− Carolyn Shoemaker (1929–2021) (news), 269 − Two contrasting galaxies in Coma Berenices Astronomical Photography for Amateurs (H.
− David Sinden (1932–2005): A life in optics, 81 (news), 121 H. Waters, 1921), 113;
Journal of the BAA: Index to vol. 131 (2021)
Observational Astronomy for Amateurs & Obituaries Variable stars
Amateur Astronomer’s Handbook (J. B. − Iain Nicolson (1945–2020), 115 − Betelgeuse’s 2021 April minimum agrees with
Sidgwick, 1955), 182; − Mike Tabb (1939–2020), 10 prediction of 430-day period (news), 211
Mysteries of Space & Time & Clouds, Rings – Peta Ann Bosley (1954–2021), 389 − Nebulae, clusters & variable stars (news),
and Crocodiles: by spaceship to the planets – Peter W. Parish (1951–2020), 319 119
(H. P. Wilkins, 1955), 325 − Ronald James Livesey (1929–2021), 186 − Observing the 2017–’19 primary eclipse of
− From the Journal archive (news), 15, 80, 144, Observing VV Cephei with a low-resolution spectro-
216, 277, 349 − Ancient Light : Imaging a quasar without a scope, 217
– J. H. Schröter and the ghost mountains of Ve- telescope (news), 120 – Observing the bright symbiotic variable star Z
nus, 350 – Atmospheric dispersion, Part I: Problem & so- Andromedae (news), 390
− Space travel and Richard Woolley (ltr.), 386 lution (news), 276 – Rare outburst of the dwarf nova LL Androme-
− Three Girton astronomers (news), 141 – Atmospheric dispersion, Part II: Orientation dae (news), 343
Instruments and observatories & adjustment (news), 348 – Two more novae and a bright maximum of
− Convertible telescopes (news), 215; (ltr.), 323 − Dealing with dew (news), 14 Mira (news), 270
− Demystifying calibration frames (news), 143 − Demystifying calibration frames (news), 143 Venus
– Equipment for sale (news), 337 − In brief (news), 6, 69, 133, 200, 269, 337 – J. H. Schröter and the ghost mountains of Ve-
− Observations of Mars & Saturn at the Lowell − An interview with Alexandra Hart (news), 74 nus, 350
Observatory in 2018 July, 37 − Observations of Mars & Saturn at the Lowell − The 2019–’20 eastern elongation of Venus,
− The taxonomy of mountings (news), 79 Observatory in 2018 July, 37 Part I: Observations of the dayside, 175
Jupiter − Sky notes (news), 60, 124, 192, 260, 328, 396 − The 2019–’20 eastern elongation of Venus,
− Mutual phenomena of Jupiter’s moons in − Solar observer Monty Leventhal receives Part II: Observations of the nightside, 224
2021 (news), 72 BAA Ridley Grant (news), 205
− Jupiter in 2020 (news), 202 − The taxonomy of mountings (news), 79
Mars − Watching the wheels − 24-hour star trails from
− The first Martian helicopter flights − and Kitty Oxfordshire (ill.), 197 Author index
Hawk (news), 137 Radio Astronomy Section
− Mars in 2020–’21: Third interim report − The Radio Astronomy Section in 2020 (news), Abel P. G.
(news), 208 206 − The 2019–’20 eastern elongation of Venus,
− The opposition of Mars, 2014: Part I, 42 – Radio Astronomy Section: Autumn Pro- Part I: Observations of the dayside, 175
− The opposition of Mars, 2014: Part II, 105 gramme 2021, 318 − The 2019–’20 eastern elongation of Venus,
− The opposition of Mars, 2016: Part I, 227 Reviews Part II: Observations of the nightside, 224
– The opposition of Mars, 2016: Part II, 291 – Neptune: From grand discovery to a world re- Abel P. G. & Lawrence P.
Meetings and Courses (held by Zoom & vealed (Sheehan et al. [Eds.]), 387 − Observations of Mars & Saturn at the Lowell
streamed online) − Planetary Astronomy (Pellier [Ed.]), 255 Observatory in 2018 July, 37
− BAA Summer Meeting, 2020 July 4, 58 – Solar Astronomy: Observing, imaging & Aerts L.
− BAA Autumn Meeting, 2020 September 5, 122 studying the Sun (Viladrich [Ed.]), 387 − The Straight Wall at high resolution (ill.), 133
− BAA Annual General Meeting & Ordinary − Tycho Brahe and the measure of the heavens Ahad A.
Meeting, 2020 October 28, 188 (Christianson), 56 − Observing asteroidal occultations from cislu-
− Historical Section Meeting, 2020 November − Vera Rubin: a life (Mitton & Mitton), 184 nar space (ltr.), 251
21, 187 − What stars are made of: The life of Cecilia Allen H.
− BAA Christmas Meeting, 2020 December 5, Payne−Gaposchkin (Moore), 118 − Observing the 2017–’19 primary eclipse of
256 Saturn, Uranus & Neptune Section VV Cephei with a low-resolution spectro-
− BAA Ordinary Meeting, 2021 January 23, 258 – Neptune in 2014–’15, 287 scope, 217
– Radio Astronomy Section meeting, 2021 – Two papers on amateur observations of Ura- Archer M.-L. et al.
March 12, 318 nus & Neptune (news), 269; (ill.), 265 − Answers to the 2020 Christmas Quiz (news),
– BAA Ordinary Meeting, 2021 March 31, 326 – Uranus during the 2015 apparition, 283 16
– BAA Spring Meeting, 2021 April 24, 394 Solar System – BAA Christmas Quiz for 2021 (news), 338
– BAA Ordinary Meeting & George Alcock – Family portrait of the Planets (ill.), 4 Arditti D.
Memorial Lecture, 2021 May 26, 395 − Now you see it, now you don’t (mtg.), 258 − Convertible telescopes (news), 215
– Come to the BAA’s 2022 Winchester Week- Space exploration − Dealing with dew (news), 14
end (news), 388 − Astronomical observing and space explora- − Demystifying calibration frames (news), 143
− Winchester 2021 goes online, 64 tion (ltr.), 57 – Equipment for sale (news), 337
Meteors − The first Martian helicopter flights − and Kitty – From the President (news), 335
− The Earth-grazing meteor of 2020 September Hawk (news), 137 − Nominations invited for the eighth Sir Patrick
22 (news), 11 − Latest news in spacecraft exploration of com- Moore Prize (news), 201
− Observing and recovering the Winchcombe ets and asteroids (mtg.), 58 − Sky notes (mtg.), 259
meteorite (news), 134 Spectroscopy − The taxonomy of mountings (news), 79
Moon − Observing the 2017–’19 primary eclipse of Arditti D. & Lorrain A.
− Aristarchus – the bands disbanded? (news), 54 VV Cephei with a low-resolution spectro- – The BAA at Burlington House: The end of an
− Pete Lawrence’s ‘Thin Moon’ hunt (ltr.), 251 scope, 217 era (news), 336
− Searching for lunar domes in the Sinus Iridum Sun Bailey K.
region: identification of a dome termed L1, 93 − A comparison of BAA Solar Section white- – Uranus during the 2015 apparition, 283
− Some old observations of the Aristarchus light measurements, 22 Barrett S.
bands (ltr.), 181 – The five greatest sunspot groups, 375 − Ancient Light : Imaging a quasar without a
− The Straight Wall at high resolution (ill.), 133 − An interview with Alexandra Hart (news), 74 telescope (news), 120
Novae and supernovae − Pro-am collaboration on a modern reconstruc- Barton W.
− A bright nova in Cassiopeia heralds spring tion of Carrington’s sunspot observations − Historical Section Meeting, 2020 November
(news), 132 (news), 140 21 (news), 187
− Novae appear in Cassiopeia & Perseus (news), – Solar Section (news), 12, 76, 138, 212, 272, − Tycho Brahe and the measure of the heavens
10 344 (Christianson) (rvw.), 56
− Novae in Cassiopeia & Hercules: a case of the − Sunspot groups without active region numbers, Barton W. & Frost M.
tortoise and the hare? (news), 210 145 − Three Girton astronomers (news), 141
Journal of the BAA: Index to vol. 131 (2021)
Baum R. Frost M. & Barton W. − Planetary Astronomy (Pellier [Ed.]) (rvw.), 255
– J. H. Schröter and the ghost mountains of Ve- − Three Girton astronomers (news), 141 Longshaw N.
nus, 350 Frost M. & James N. − Early history of the shadow bands in Aris-
Bonell A. − A Patagonian eclipse (news), 6 tarchus (ltr.), 386
− Now you see it, now you don’t (mtg.), 258 Gibson B. Lonsdale M. et al.
Brantingham S. − How the Universe will end (mtg.), 122 – Using a lunar eclipse to measure the diameter
− Aurora & Noctilucent Cloud activity (news), Halls B. of the Earth’s shadow (news), 320
8, 69, 136, 200, 275, 347 − Partial solar eclipse, 2021 Jun 10 (ill.), 199 Lorrain A.
− Aurora, STEVE and noctilucent clouds Haymes T. − The BAA Awards for 2020 (news), 3
(mtg.), 59 − Some merit in observing asteroidal occulta- − From the President (news), 3, 67, 131, 199, 267
Brazell O. tions from the ground (ltr)., 323 − President’s Review of the Year, 2019−2020
− Planetary nebulae in Gemini (news), 55 Haymes T. & Pratt A. (mtg.), 188
− Sky Notes (mtg.), 326 − A well-observed double star occultation – Lorrain A. & Arditti D.
Brunsden E. SAO 93840 (HO 328) (news), 73 – The BAA at Burlington House: The end of an
− Fantastic planets and how to find them (mtg.), Hearn P. era (news), 336
256 – Radio Astronomy Section: Autumn Pro- Lorrain A., King G. et al.
Bryant G. gramme 2021, 318 – Report of the Council, Trustees’ Report and
– Peta Ann Bosley (1954–2021) (obit.), 389 – Radio Astronomy Section meeting, 2021 financial results for 2020−2021, 299
Cattermole P. March 12, 318 McGee H.
− Iain Nicolson (1945–2020) (obit.), 115 Hetherington B. − Index to Journal, vol. 130 (2020), facing 32
Chuter J. − Centenaries for 2022 (news), 384 McIntyre M.
− From the BAA archives (news), 51, 114, 183, Hewitt N. − Watching the wheels − 24-hour star trails from
250, 324, 388 − Sky notes (news), 60, 124, 192, 260, 328, Oxfordshire (ill.), 197
− From the Journal archive (news), 15, 80, 144, 396 McKim R.
216, 277, 349 Holmes S. – BAA Instruments for sale (news), 268
– Neptune: From grand discovery to a world re- − Of plants & planets: speculating on the flora − The first Martian helicopter flights − and Kitty
vealed (Sheehan et al. [Eds.]) (rvw.), 387 of Kepler-186f (ltr.), 385 Hawk (news), 137
Cook J. James N. − From the BAA bookshelf (news):
− The Radio Astronomy Section in 2020 (news), − Sky notes (mtg.), 191, 395 Astronomical Photography for Amateurs
206 James N. & Frost M. (H. H. Waters, 1921), 113;
Cook J. et al. − A Patagonian eclipse (news), 6 Observational Astronomy for Amateurs &
− A comparison of BAA Solar Section white- Jennings P. Amateur Astronomer’s Handbook (J. B.
light measurements, 22 − In brief (news), 6, 69, 133, 200, 269, 337 Sidgwick, 1955), 182;
Davies A. − An interview with Alexandra Hart (news), 74 Mysteries of Space & Time & Clouds, Rings
– Come to the BAA’s 2022 Winchester Week- − Sky notes (mtg.), 256 and Crocodiles: by spaceship to the planets
end (news), 388 − Papers accepted by Council for publication in (H. P. Wilkins, 1955), 325
Devey A. the Journal: 59, 123, 191, 257, 259, 327, 395 − Mars in 2020–’21: Third interim report
– Solar Astronomy: Observing, imaging & − Peter Clark (1938−2021) (news), 194 (news), 208
studying the Sun (Viladrich [Ed.]) (rvw.), 387 − Winners of the 2020 Christmas Quiz (news), 68 − The opposition of Mars, 2014: Part I, 42
Dowdell A. Kennedy K. − The opposition of Mars, 2014: Part II, 105
− BAA Summer Meeting, 2020 July 4, 58 − Noctilucent cloud over Britain & Western Eu- − The opposition of Mars, 2016: Part I, 227
− BAA Autumn Meeting, 2020 September 5, 122 rope, 2019, 171 – The opposition of Mars, 2016: Part II, 291
− BAA Annual General Meeting & Ordinary − Ronald James Livesey (1929–2021) (obit.), 186 – Peter W. Parish (1951–2020) (obit.), 319
Meeting, 2020 October 28, 188 Kidger M. Macdonald L.
− BAA Christmas Meeting, 2020 December 5, 256 − Betelgeuse’s 2021 April minimum agrees − Vera Rubin: a life (Mitton & Mitton) (rvw.),
− BAA Ordinary Meeting, 2021 January 23, 258 with prediction of 430-day period (news), 211 184
– BAA Ordinary Meeting, 2021 March 31, 326 – Five thousand years of Jupiter–Saturn con- Macdonald P.
– BAA Spring Meeting, 2021 April 24, 394 junctions, 369 − The annular solar eclipse of 2021 June 10
Druckmüller M. & Möller A. King G., Lorrain A. et al. (news), 68
− A Patagonian eclipse (ill.), 1 – Report of the Council, Trustees’ Report and Meadows P.
Dymock R. financial results for 2020−2021, 299 – The five greatest sunspot groups, 375
− Astronomical observing and space explora- King M. − Sunspot groups without active region num-
tion (ltr), 57 − Space travel and Richard Woolley (ltr.), 386 bers, 145
– Microlensing search for exoplanets – a new Knigge C. Meadows P. et al.
pro-am project (news), 340 – Quasar unification via disc winds: from phe- − A comparison of BAA Solar Section white-
Farquharson J. nomenology to (astro)physics (mtg.), 394 light measurements, 22
− An evening with the Sinden brothers (ltr), 181 Lawrence P. & Abel P. G. Miles R.
Font A. − Observations of Mars & Saturn at the Lowell − MISSION 29P: A review of progress & a re-
− Stumbling in the dark: the search for the Uni- Observatory in 2018 July, 37 cent strong outburst of comet 29P/Schwas-
verse’s missing mass (mtg.), 123 Leatherbarrow W. J. smann–Wachmann (news), 70
Ford D. − Aristarchus – the bands disbanded? (news), 54 − Success for two sample-return missions to as-
− Prof Roger Griffin (1935–2021) (news), 141 Lena R. et al. teroids (news), 5
Foulkes M. − Searching for lunar domes in the Sinus Iridum Miles R. et al.
– Two papers on amateur observations of Ura- region: identification of a dome termed L1, 93 − Graham Salmon (1932–2021) (news), 133
nus & Neptune (news), 269 Levanthal M. Mizon R.
Fowler M. J. F. et al. − Solar observer Monty Leventhal receives − Award for lighting scheme at Wimborne First
– Observing exoplanets with the MicroObser- BAA Ridley Grant (news), 205 School (news), 52
vatory: 43 new transit lightcurves of the hot Lewis M. − CfDS braves the elements (news), 252
Jupiter HAT-P-32b, 359 – Atmospheric dispersion, Part I: Problem & – Lights & lies (news), 271
Frost M. solution (news), 276 – Light pollution, biodiversity & climate change
− What stars are made of: The life of Cecilia – Atmospheric dispersion, Part II: Orientation (news), 342
Payne−Gaposchkin (Moore) (rvw.), 118 & adjustment (news), 348 − Mike Tabb (1939–2020) (obit.), 11
Journal of the BAA: Index to vol. 131 (2021)
Mobberley M. Pratt A. et al. Mira (news), 270
− Reginald Lawson Waterfield (1900–1986), − Graham Salmon (1932–2021) (news), 133 Smith L.
eclipse chaser & comet photographer extraor- Privett G. & Potter C. – Solar Section (news), 12, 76, 138, 212, 272,
dinaire: Part I, 158 − Europlanet bid success for variable nebulae 344
− Reginald Lawson Waterfield (1900–1986), observers (news), 78 Smith L. et al.
eclipse chaser & comet photographer extraor- Quiney A. − A comparison of BAA Solar Section white-
dinaire: Part II: 1939–’86, 236 − Pete Lawrence’s ‘Thin Moon’ hunt (ltr.), 251 light measurements, 22
Möller A. & Druckmüller M. Rigopoulou D. Snodgrass C.
− A Patagonian eclipse (ill.), 1 − Lighthouses in the Universe: the tale of ultra- − Latest news in spacecraft exploration of com-
Moore S. luminous infrared galaxies (mtg.), 326 ets and asteroids (mtg.), 58
– NGC 2683 – a glorious galaxy in Lynx (news), Ringwood S. Stewart W. et al.
391 − Arthur Stanley Williams’ lens rediscovered − The Earth-grazing meteor of 2020 September
− NGC 6751 – an overlooked planetary nebula (ltr.), 57 22 (news), 11
in Aquila (news), 254 Rogers J. − Graham Salmon (1932–2021) (news), 133
− Two contrasting galaxies in Coma Berenices − Jupiter in 2020 (news), 202 Sussenbach J.
(news), 121 − Mutual phenomena of Jupiter’s moons in – Neptune in 2014–’15, 287
Morrone L. 2021 (news), 72 Tadhunter C.
– Family portrait of the planets (ill.), 4 Rowe J. – Quasars, black holes and the future of the
Nichol J. − Observing and recovering the Winchcombe Milky Way (mtg.), 394
− David Sinden (1932–2005): A life in optics, 81 meteorite (news), 134 Tarver W.
Phillips P. Samson W. B. − Nominations for the Ballot for Council &
− Partial solar eclipse, 2021 Jun 10 (ill.), 199 − Using Gaia DR2 data to determine the dis- Board of Trustees (news), 53, 116
Pickard R. tances of young star clusters and their distri- − Your vote for the BAA Trustees & Council
− Nebulae, clusters & variable stars (news), 119 bution in the galactic plane, 97 (news), 200
Potter C. Sawers A. Tatum J.
− Open clusters for the summer months (news), − Memories of Dr Edward Yeadon (ltr.), 57 − Memories of Venus occulting Regulus in 1959
185 Shanklin J. (ltr.), 323
– Our friends in the north (news), 321 − The brighter comets of 2017, 27 Taylor C.
Potter C. & Privett G. − Comet prospects for 2022 (news), 392 − Some old observations of the Aristarchus
− Europlanet bid success for variable nebulae – The 2021 George Alcock Memorial Lecture: bands (ltr.), 181
observers (news), 78 George Alcock goes to Antarctica, 278 Teague T.
Poyner G. Shears J. − Pro-am collaboration on a modern reconstruc-
– Observing the bright symbiotic variable star Z − A bright nova in Cassiopeia heralds spring tion of Carrington’s sunspot observations
Andromedae (news), 390 (news), 132 (news), 140
Pratt A. − Convertible telescopes (ltr.), 323 Thomas G.
− The artwork of Ron Livesey (ltr.), 251 − Novae appear in Cassiopeia & Perseus (news), − The return of noctilucent cloud (ill.), 129
Pratt A. & Haymes T. 10 Webster N.
− A well-observed double star occultation – − Novae in Cassiopeia & Hercules: a case of the – Pickering’s Triangle (ill.), 335
SAO 93840 (HO 328) (news), 73 tortoise and the hare? (news), 210 Whillock M.
Pratt A. & Stewart W. – Rare outburst of the dwarf nova LL Androme- − Partial solar eclipse, 2021 Jun 10 (ill.), 199
− The Earth-grazing meteor of 2020 September dae (news), 343 Younis M.
22 (news), 11 – Two more novae and a bright maximum of − The Beehive Cluster, Messier 44 (ill.), 65

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