On 15th July, there could be seen an occultation, a grazing occultation, or a conjunction of the Moon and Jupiter depending on your location in the British Isles.
John Vetterlein in Orkney was able to capture a nice range of photos of the conjunction.
You can see more of John’s photos on his own Blog
On Sunday morning, 2012 July 15, observers in southern Britain will have the chance to see a rare and splendid sight: Jupiter and its moons gliding behind the rugged horizon of the Moon’s north pole. This is one of a series of lunar occultations of Jupiter, and the only one which will be visible in a dark or twilight sky from the UK. The northern limit crosses England, giving a grazing occultation along a broad band from East Anglia to SE Wales and Cornwall. Times will vary considerably from place to place, but the full event spans approx. 01:51 to 02:22 UT (02:51 to 03:22 BST) (from disappearance of the first satellite to reappearance of the last satellite at Greenwich).
Full details of the grazing occultation were published by Jan Meeus in the Journal of the BAA, vol.122, p.31 (2012 Feb.).
The full occultation is visible for observers all over Europe except Scandinavia, and details are posted at:
Imaging the event will be a challenge, as the movement will be too fast for normal planetary imaging techniques, and it will be at low altitude in the dawn sky. Short monochrome exposures with a red or infrared filter would optimise the sharpness and brightness of Jupiter. These could then be combined with colour channels from longer exposures just before or after the occultation, to produce L(IR)RGB images. If you produce images, please record how they were made. Drawings will also be welcome.
BAA Jupiter Section Director
As Jupiter is now high in the evening sky, you may like to look at some recent maps of the planet which we have posted on the BAA Jupiter Section web site, to illustrate the interesting features and events over this apparition. Some were compiled by individual observers from their own images; the others were compiled by Marco Vedovato of the JUPOS team from images by many observers.
You can see the full picture here:
Also, we have posted maps of the Galilean moons, from spacecraft, with the major features labelled. The best amateur images can now record a few of these features (see our 2011 report no.2 for superb examples)! Thanks to Bjorn Jonsson and to the USGS for the base maps.
You can see the maps here:
Jupiter is still high enough for good observations, which the BAA will be happy to receive. And even naked-eye observers can enjoy the view of the planet in the evening twilight, especially as it will be alongside Venus for several days around March 15.
Earlier this year, astronomers observing the planet Jupiter noticed that it’s usually prominent Southern Equatorial Belt (SEB) – a band of darker cloud in Jupiter’s otherwise pale surface – had disappeared. This was not the first time it had happened: in 1973 when Pioneer 10 flew past Jupiter the belt was absent, and it vanished again in the early 1990s.
But there are now signs that the Southern Equatorial Belt is reviving. The BAA Jupiter Section Director John Rogers explains:
“A spectacular bright plume has appeared in Jupiter’s faded South Equatorial Belt, and is expected to become the source of spectacular disturbances leading to revival of the belt.
“This rapidly brightening plume is so energetic that we can confidently expect it to develop into the SEB Revival. The SEB Revival is usually spectacular, so we can expect impressive and rapidly changing disturbances over the next 3 months, until the end of the apparition. As the SEB is so thoroughly whitened, and the outbreak has appeared in an isolated location, we can hope to see the phenomena displayed in their most complete form.
“Normally, disturbances continue to arise at the same source, and spread out in three branches: northern and central branches, prograding, and a southern branch, rapidly retrograding. If they develop as usual, both the central and southern branches could impact on the Great Red Spot in January. Observers should monitor all aspects of the spreading disturbances, but also monitor other longitudes, as a secondary source might also appear. Observers have the chance to make this the best-observed SEB Revival ever.”
The initial observations of the bright plume were a truly international affair, as John Rogers explains:
“The bright plume was discovered by Christopher Go (Philippines) in an image which he took on Nov.9 at 12:30 UT. He announced it immediately by e-mail, and it was confirmed 11-12 hours later by Donald C. Parker (Florida, USA) and Gary Walker (Georgia, USA), when it was already brighter.
“Don Parker’s images included infrared, ultraviolet, and 0.89 micron (methane) bands, and the new spot was amazingly bright in all of them, showing it to be a convective plume of cloud reaching to very high altitude. Indeed it was already visible in a methane-band image taken in poor seeing by A. Yamazaki (Japan) on Nov.9 at 14:14 UT. On its third rotation, Nov.10 from 09:00 UT onwards, images by many Japanese observers and by C. Go and T. Akutsu (Philippines) confirm that it is the brightest spot on the planet in all wavebands. Its longitude is L2 = 290 (L3 = 149). (The Great Red Spot is at L2 = 159.)
“This plume has appeared inside a cyclonic circulation, called ‘barge B2′, which had been very dark a year ago, but turned white in 2010 May-June. Details of this are available on the BAA’s Jupiter Section website:
http://www.britastro.org/jupiter/2010report08.htm [Figure 11].
“Thus the former barge already comprised a white spot, but it was not methane-bright (up to Nov.7: Chris Go). It was still quiet on Nov.8 (Sadegh Ghomizadeh, Iran). So the much brighter plume was new on Nov.9. We had already suggested that the SEB Revival might begin with such a plume in one of the barges, as it did in 2007; the event is a striking confirmation of this hypothesis.”
This week’s BAA Picture of the Week is of Jupiter, imaged by Manos Kardasis from Greece, on November 6 & 7 2010.
Manos writes: “I took advantage of the rare good seeing conditions over Greece in the latest days to do a Hi-Res Strip Map. Unfortunately on the 6th of Nov. the seeing got worst after midnight so I took the risk among clouds to fill the bad parts in the following night.”
This week’s BAA Picture of the Week is of the planet Jupiter, taken by Peter Edwards from West Sussex on 25th October at 22:39 UT.
Imaged using a Celestron C11 at f/20 and a DMK21AU04 camera with RGB filters.
The BAA Jupiter Section membership consists of (i) all observers contributing observations within the last two years; (ii) other BAA members on the mailing list for Section Circulars.
The Section aims
- to encourage people to observe Jupiter, and to provide advice on doing so
- to monitor the visible changes in the atmosphere of the planet, and to produce scientifically valuable reports on these changes.
Everything seen on Jupiter is clouds, and our aims are to monitor the currents, colours, and disturbances in the planet’s atmosphere. The BAA has been doing this systematically since 1891, and the published Section Reports comprise an incomparable record of changes on the planet. Our observations are still revealing new patterns and new variations. Changes occur on many timescales. The overall pattern of dark belts and bright zones is permanent but can change temporarily, for a matter of years or months. Sometimes there are striking colour changes too. There are many ’spots’ – circulations and storms, which reveal the numerous currents in the atmosphere. They range from the Great Red Spot, which has existed for three centuries, to turbulent disturbances which may change dramatically within a few days. (Full details of the planet are described in Ref.3.) The standard nomenclature of belts and zones and currents has been refined [Refs.3,4], since the Voyager spacecraft discovered how these visible features are bounded by a regular pattern of jetstreams in fixed latitudes
Although our reports are now based mainly on CCD images, visual observers still have a chance of spotting new phenomena. In addition, visual observers can monitor the major events on the planet independently, and we will continue to publish visual records of the planet along with the analysis of images.
We have reviewed our conventions, as they differ from the conventions adopted more recently by professional astronomers, and we will adopt the following in future:
- Longitudes (in Systems I or II) will be abbreviated as L1, L2 (rather than lambda-suffix-1,2, as in the past). Central meridian longitudes will be abbreviated as CM1, CM2 (rather than omega-suffix-1,2). This change is to make our reports compatible with e-mail.
- We will continue to use longitude System II for non-equatorial latitudes, rather than System III which is used by professionals. The reasons are: (i) All historical observations have been in System II. (ii) The Great Red Spot, and major features associated with it in the SEB, are almost stationary in System II, so it is easy to point observers to them by L2. However we will give data for conversion to System III in all reports, and we ask imagers to report CM longitudes in all three systems (CM1, CM2, CM3).
- We will continue to publish images and drawings with south up, for two reasons: (i) This is how visual observers (in the northern hemisphere) see the planet, and we want to maintain the link between our reports and the direct experience of observers. (ii) With this orientation, both longitude and time increase from left to right, allowing a natural integration of numbering systems, cylindrical projection maps, and longitude/time charts.
We encourage visual observations both by beginners and by more experienced observers. While major features such as belts and equatorial dark projections can be seen with an 8-cm telescope, satisfactory observations require a telescope of aperture at least 15 cm (6 inches). Beginners should try the following methods of observation, so that they can make useful records if they ever see anything unexpected on the planet. For more detailed advice, please see the BAA observing guide [ref.5] or the Director’s book [ref.3]. More advanced observers may wish to specialise as suggested.
(1) Drawings. Most people like to draw what they see, and this is a skill that takes some practice to develop. Good drawings are welcomed as illustrations of the general appearance of the planet, and may occasionally be useful as records of special events. The standard size for a disk drawing is 64 by 60 mm.
A more advanced option is to develop one’s style of drawing (or even colour painting) so as to combine observational accuracy with artistic quality. Another option is to make strip-maps (cylindrical projection maps) of part or all of the planet, one or more times during an apparition. This gives a valuable overview of the pattern of belts and spots around the planet.
(2) Longitude measurements. Useful longitude measurements of spots can be made by timing their ‘transits’. This does not require any special equipment: one just estimates the time at which the spot crosses the centre-line of the disc (the central meridian). The observer should give the transit time to the nearest minute (which corresponds to 0.6 deg. of rotation in longitude), and calculate L1 or L2 from the tables in the BAA Handbook. Any observer who sees an unexpected, possibly novel feature on the planet is urged to make a transit timing.
An advanced observer might wish to make transits systematically through an apparition, accompanying them with sketches, as has been done by the Jupiter Section in the past. If transits are accurate and numerous enough (so that the observer’s personal equation can be established), the observer could plot his/her own charts to follow spots on their different currents over several months, and these data could be used as a supplement to image-based analysis. Observers doing systematic transit timings are urged to type in their results in JUPOS format, so that they can be put into the JUPOS database and plotted on the charts. For the format, see the web site [Ref.6].
(3) Colour and intensity estimates. Systematic verbal estimates of colours of belts and zones may be useful, if made with a reflecting telescope of at least 25 cm (10 inches). Although there is considerable scope for artefacts, e.g. due to subjective contrast effects, this is also true of colour CCD images, e.g. due to use of different filters and image-processing. Therefore, visual colour estimation is still a worthwhile project.
Some observers have made intensity estimates of belts and zones through red and blue filters and this should also be a means of recording colour. A project for an experienced observer could be to systematically compare visual colour impressions, visual red-minus-blue estimates, and colour impressions on processed CCD images, and to calibrate them against absolute intensity measurements on multi-filter CCD images.
Estimates of the intensity (darkness) of belts and zones can be made numerically, on a scale from 0 (brightest) to 10 (black sky). They are inevitably subjective so are only worthwhile if done systematically and repeatedly within the context of a more detailed observational programme. Observers who make colour or intensity estimates should tabulate and average them for the whole apparition, and note any significant changes.
(4) Observations of satellite phenomena. The transits, shadow transits, eclipses, and occultations of the four galilean satellites are among the most striking phenomena that a beginner can observe. Although observations are not likely to have any scientific significance, observers may like to make accurate drawings of these phenomena, especially when several are occurring at once. Every six years, the satellites occult and eclipse one another, and it is interesting to plot visual light-curves of the mutual eclipses.
Contributing visual observations: New report forms have been designed (as word or pdf). These will be sent to members who request them from the Director, either as hard copy (in which case, please make extra photocopies yourself), or as Word files by e-mail. Observers are invited to use whichever form is more suitable for the observations they choose to make, or to adapt them. Please report observations about once a month during an apparition, and let the Director know at once if you see anything unusual happening on the planet.
Visual observations should be sent to the Director, either as JPEG scans by e-mail (though please keep the number and size of files reasonably small), or as original drawings or good photocopies by post. Send an e-mail address or a stamped addressed envelope if you would like acknowledgement. If better copies are required for publication, we will request them from you. If you would like to form an informal ‘news-group’, we will be happy to put you in touch with other members who also send drawings by e-mail.
CCD and Webcam Imaging
CCD imaging has transformed the amateur record of the appearance of Jupiter. Images can enhance Jupiter’s rather low contrast, and can provide accurate measurements of both latitude and longitude. For the Jupiter Section, these measurements are now made using the computer-based JUPOS system, and they enable us to track numerous features large and small.
In general any telescope of good quality is suitable. For quality refractors 10cm and larger aperture will produce good results. For reflectors 15cm and larger aperture will produce very good resullts. Telescopes of 20-40cm can produce extraordinarily detailed images under steady seeing conditions.
Affordable webcam technology now allows observers to capture a great amount of detail on Jupiter. If a colour webcam is to be used (such as the Philips ToUcam) the observer should employ an IR blocking filter to ensure the image is not “polluted” with IR signal (since CCD chips are very sensitive to the wavelengths.)
RGB imaging can also easily be undertaken with a set of good filters (again ensure that the IR signal is blocked either by use of a seperate IR blocking filter or IR blocking coated colour filters. Images need to be obtained quickly for combination into a tri-colour image due to Jupiter’s fast rotation. The observer has only 2-3 mins at the very most before rotation induced smearing will occur.
Image processing, using Registax or other software, is necessary to bring out the planet’s limb, and is desirable to enhance contrast and perhaps to sharpen edges. Such image-processing should be done judiciously with awareness of the artefacts that it can create; check that there are not conspicuous rings around satellite shadows, nor any saturated white areas in the image. Sharpening in particular may enhance the appearance but make it less reliable.
Images in different filters can be very informative as one sees different levels in the atmosphere. Near-infrared (~800 nm) images show much small-scale detail as they penetrate some way into the main clouds. Observers with large telescopes and good CCD cameras can also take images in the ultraviolet (~360 nm) and the methane absorption band (890 nm), which reveal the high hazes in the atmosphere.
For Further technical information and advice on CCD/Webcam imaging of Jupiter please contact Damian Peach.
Please send images, by e-mail or on disk, to Hans-Joerg Mettig or Damian Peach and also send any particularly good or important images to the Director. They are more likely to be used for analysis if sent to us directly rather than just being placed on a web site. You are also encouraged to send copies of images to two international archive sites (both new in 2005):
1) International Outer Planets Watch firstname.lastname@example.org where professional astronomers keep an up-to-date archive of images on their web site, managed by Dr. Jose Rojas: http://www.pvol.ehu.es/
Filenames must be written in the order year-month-day, followed by the observer’s initials; e.g. 2003feb01_abc. Although the IJW database uses the format abc030201 to encode the initials and date, we prefer to avoid post-millennial and trans-atlantic confusion by writing the year in full, and using a 3-letter abbreviation for the month. Please include the same information in the subject line of your e-mail. You may include several images from one night in one file. If the file contains a single image, please include the time (always in UT, and preferably accurate to a tenth of a minute) in the filename, to facilitate filing in the JUPOS database; thus, 2003feb01_23305_abc (for an observation on 2003 Feb.1 at 23h 30m 30s UT by observer ABC).
Please write all essential data on the image (not as a separate text file). This should include the full date and time (UT); CM1, CM2, CM3; your name, and the colour channel(s) used. If you use different cameras or telescopes, or observe from different countries during the year, it is useful to have this information on the image also.
Like all amateur recorders, we strongly prefer south up in images, as noted above. We recommend that you make the belts horizontal, because images have to be horizontal if used for montages or maps. Unnecessary rotations may degrade resolution.
The preferred format is a JPEG file of ‘high’ quality (not ‘maximum’, to avoid very large files, but not ‘medium’ as this may degrade the image). Please use enough pixels to preserve the full resolution of the original image.
Analysis of observations
The main quantitative analysis is measurement of longitudes and latitudes of spots, and tracking them in longitudinal drift charts. This is now done from CCD images using the computer-based JUPOS system, created by Hans-Joerg Mettig and Grischa Hahn [ref.6&7].
This allows for:
–Interactive measurement of positions of spots from images on screen (using any image format);
–Manual input of longitudes from visual transits, if these are provided as a consistent set tabulated in JUPOS format (see the web site);
–Output as longitudinal drift charts.
Section Reports and Circulars
Formal printed Section Circulars are now being discontinued, in favour of more frequent e-mail bulletins. The principal address list will be the e-mail address list, comprising Section members in the UK and all contributors worldwide. E-mail bulletins are sent out whenever appropriate (approximately once a month during apparitions). Printed text copies can be sent to members in the UK if you supply the Director with some stamped addressed envelopes.
We expect to publish full reports for each jovian apparition in the BAA Journal in the usual style. Important events are also reported the news columns of the Journal, and in BAA Circulars.
1 Heath A. Letter. J.Brit.Astron.Assoc. 111 (no.1), 47 (2001); & replies by Rogers and Graham.
2 Macdonald L. ‘BAA Update: Meeting of the Jupiter and Saturn Sections…’ J.Brit.Astron.Assoc. 110 (no.6), 338-339 (2000).
3 Rogers JH, The Giant Planet Jupiter (Cambridge University Press, 1995).
4 Rogers JH. ‘The pattern of jetstreams on Jupiter: correlation with Earth-based observations and consequences for belt nomenclature.’ J.Brit.Astron.Assoc. 100 (no.2), 88-90 (1990).
5 BAA Observing Guide (2002).
6 Mettig H-J & Hahn G: http://www.jupos.org
7 Rogers JH & Mettig H-J. ‘Jupiter in 1998/99.’ J.Brit.Astron.Assoc. 111 (no.6), 321-332 (2001).
8 Rogers J. ‘Jupiter in 1999/2000, Part II: Infrared wavelengths.’ J.Brit.Astron.Assoc. (2003, in press)
This blog post is taken from a news bulletin issued by Dr John Rogers, the Director of the BAA Jupiter Section, about the 2010 June 03 impact on Jupiter.
A new impact has been detected on Jupiter. This time the impact flash was recorded directly, by two independent observers, both amateur astronomers. It was first reported by Anthony Wesley (Australia), and confirmed by Chris Go in a video taken at exactly the same time: 2010 June 3, 20:31:29 UTC. It was a very bright flash lasting about 2 seconds, so there can be no doubt that it was an impact; no internal event in Jupiter would produce such a bright brief flash.
It was in the faded South Equatorial Belt (SEB), about 50 deg. preceding the central meridian; Wesley’s preliminary measurements put it at Longitude L2 = 342.7, L3 = 159.4, Latitude 16.1 deg.S.
Nothing further was seen at the impact site in the half-hour before it disappeared round the limb. When it reappeared, the next morning around 03:30 UT , observers in England, France and Italy looked for an impact spot but recorded nothing definite. However, the images were at low resolution (due to the low altitude and bright dawn sky), so the images do not exclude a smaller scar. Observations of this site over the next few days will be very important.
|Amateur astronomers Anthony Wesley (whose video this is) of Australia and Christopher Go of the Philippines have independently observed an impact event on Jupiter. The strike occurred at 20:31 UT on June 3rd, 2010 and produced a bright flash of light in the giant planet’s cloudtops.
Even if no ’scar’ is detected, this would not be surprising. The direct imaging of the SL9 impacts in 1994 by the Galileo spacecraft showed a bright flash a few seconds long like this one even for a small fragment which produced virtually no scar, probably because a small impactor can explode high in the atmosphere. So, impacts like this could be frequent, but never before recorded, and still consistent with the rarity of larger impacts that leave obvious traces.
By the way: Uranus is 0.5 degrees north of Jupiter at present: a good opportunity to compare the two giant planets.