Here’s a (slightly off-topic) fun event for you to take part in over the festive season: waving at the international space station! You can find out where and when the ISS will be in your sky at http://www.heavens-above.com
A celebration of human solidarity during the holiday season
For one week beginning Friday, 24 December, humans around the world
will show their solidarity with their fellow humans in space (and
on Earth) by waving at the International Space Station (ISS) as she
passes overhead at 17,500 mph (28,000 kmph). Participants,
recruited through Twitter, are encouraged to share their waves —
either alone or as part of an ISSwave tweetup (a physical gathering
of twitterers, or tweeps) — by tweeting their zip/postal code and
the hashtag “#ISSwave” along with photos and videos of their waves,
thoughts, holiday wishes for the astronauts and cosmonauts, etc.
Participants’ waves will be registered in real-time at
target="_blank">www.isswave.org. Astronauts and
cosmonauts aboard the International Space Station may even film
themselves waving back at ISSwave participants. At least two
astronauts, including Ron Garan, have voiced their support for
ISSwave in emails and tweets. The idea for the wave emerged through
a serendipitous twitter exchange among Twitter acquaintances and
regular ISS watchers Lucy Rogers (
Richard P. Grant (@
target="_blank">rpg7twit) and Karen James (@
discovered that watching ISS passes is even more exciting when done
together with other humans, whether they are standing right next to
you or watching from afar. To know that you are not the only one
looking up in awe at this spectacle of human ingenuity and
cooperation speeding across the night sky creates a special
connection between us. “The first time I watched an ISS pass I was
surprised by how much it affected me,” said Karen James. “‘We made
that’, I thought, ‘there are humans up there!’ All of my worries
just seemed so tiny in the face of this symbol of human achievement
and cooperation. I want to share that experience with other humans
and also show my support to the ones living and working aboard the
station.” ‘“I’d always wave up at the ISS if I saw it pass
overhead,” says Lucy Rogers. “Someone laughed and said the
astronauts wouldn’t see me.” So she asked on Twitter if anyone else
waved – a lot of people did – and the communal ISS waving
began. “When Karen moved to the USA she saw the ISS at a
different time to us in Europe – which prompted the idea of a
round-the-world wave,” she says. We see the ISS because it is lit
by the Sun. Sunlight reflects off it’s solar panels in the same way
it glints off windows here on Earth. As the ISS travels round the
world, the reflection can be seen in a broad sweep across the
Earth. Due to the angles involved between the Sun, ISS and our
location on Earth, sometimes we see bright, high passes and
sometimes we can’t see it at all. During the week 24th – 31st
December, most places on the Earth should get a good view of it at
some point. The three formed the Twitter account @
target="_blank">ISSwave to coordinate, promote and
provide updates on the event. Their hope is that seasoned and
novice ISS watchers alike will experience the startlingly emotional
experience of an ISS pass, amplified by solidarity with thousands
of others watching around the world. Additionally, the team hopes
the buzz around ISSwave will persuade those who have never watched
an ISS pass to participate, marking an increase in awareness about
the International Space Station and the existence of a community of
space enthusiasts on Twitter (“spacetweeps”). The wave also
celebrates the 10th anniversary of continuous human presence in
space (ISS10years) on 2 November 2010 and the 50th anniversary of
Yuri Gagarin’s flight into space — the first human spaceflight — on
April 12th 2011 (
target="_blank">www.YuriGagarin50.org).
Zeta Orionis Regon - Graham Relf
This week’s BAA Picture of the Week is of the nebulosity near Zeta Orionis: NGC 2023 & 2024, IC 434 and B33 (Horsehead).
Canon EOS 5D MkII at prime focus of SkyWatcher 254mm f/4.8 Newtonian 18 x 30s at ISO 6400. 2010 Dec 11, 23:10:27 – 23:21:37 UT
Graham writes: “This was taken with an unmodified Canon DSLR camera. I had previously believed that it was not possible to photograph the Horsehead Nebula without removing the infra red filter from in front of the CMOS detector in a digital SLR camera but this photo proves otherwise. My previous inability to photograph the Horsehead must have been due to light pollution at my suburban observing site. The present photo was taken from the village of Rookhope, high in the North Pennines. No filters have been used here. Clearly the emission nebula behind the Horsehead is reddish, so in other published photos that I have seen the predominant red colour was not just due to using H-alpha filters.”
Early this Tuesday morning, on 21 December, the day of the winter solstice, there will be a total eclipse of the Moon. The Moon first enters the outer, penumbral part of the Earth’s shadow at 05:29 UT, and the partial eclipse begins at 06:32 UT. The eclipse first becomes total at 07:40 UT, reaches maximum at 08:17 UT, and ends at 08:53 UT.
The entire eclipse will be visible after local midnight from Canada, the USA, central America and the north-western tip of South America. The eclipse occurs at the Moon’s descending node in eastern Taurus, four days before perigee. The Moon will be full at 08:13 UT. Further information on this eclipse may be found at:
http://eclipse.gsfc.nasa.gov/OH/OH2010.html#LE2010Dec21T
From southern parts of the British Isles, the initial umbral phases will be visible, but the Moon will be dropping down into the western sky as dawn approaches. From such locations, when totality begins at 07:40 UT, the Moon will be very low in the west-north-western sky, close to the horizon and in a rapidly brightening sky. From locations in Scotland and Northern Ireland, totality will be visible in its entirety, but the Moon will be low down after the time of greatest eclipse (08:17 UT).
From London, sunrise is at 08:04 UT with moonset just seven minutes later.
The table below lists the times of moonset for various locations in the British Isles:
Location Moonset (UT)
Brighton 08:08
London 08:11
Bristol 08:21
Birmingham 08:25
Swansea 08:28
York 08:30
Liverpool 08:35
Newcastle-upon-Tyne 08:39
Dublin 08:48
Belfast 08:55
Glasgow 08:57
Aberdeen 08:58
The umbral phase lasts from 06:32 UT until 10:01 UT. During totality, the Moon tracks through the northern part of the Earth’s umbral shadow, so for those observers watching it high up in a clear sky, the southern half of the totally eclipsed Moon will most likely appear considerably darker than the northern part.
One never quite knows how dark or how bright a lunar eclipse will be. Everything depends on the conditions in the Earth’s upper atmosphere through which all light falling onto the shadowed Moon has to pass. There have been eclipses when the Moon has been difficult to find even with a telescope, while at other eclipses it has remained bright red or vividly coloured.
For observers in the British Isles, the very low elevation of the Moon during the total phase means that it is not possible to predict the exact brightness distribution in the umbra, so observers are encouraged to estimate the brightness using the Danjon scale at different times during totality. Note that it may also be necessary to assign different Danjon values to different portions of the Moon (i.e., north vs. south).
For an explanation of the Danjon scale of lunar eclipse brightness visit:
http://eclipse.gsfc.nasa.gov/OH/OHres/Danjon.html
The 2010 December 21 total lunar eclipse belongs to Saros 125, a series of 72 eclipses in the following sequence: 17 penumbral, 13 partial, 26 total, 9 partial, and 7 penumbral lunar eclipses.
There will be two total lunar eclipses in 2011, on 15 June and 10 December, but neither will be visible in its entirety from the British Isles.
The BAA Lunar Section will be pleased to receive observations of the lunar eclipse. See the Section’s webpage at http://www.baalunarsection.org.uk/ for more details.
John Mason
BAA Press and Publicity Officer
Jupiter
This week’s BAA Picture of the Week is probably the finest ground based image of Jupiter, ever, by Damian Peach.
Damian writes:
“Jupiter with the GRS, Ganymede and Io. The Jupiter is from Sep 12th while the moon images were taken, aligned and processed seperately and positioned for aesthetic value.
Ganymede clearly shows the brilliant Osiris ray crater region at top while Marius and Galileo regio are also nicely visible. Ganymede was 1.84″ in apparent diameter – larger than in most years.”
On 8 Dec 2010 two spots were recorded on Saturn at the same latitude.
Firstly, a bright spot was recorded close to the central meridian in an image taken at 02:12UT by Sadegh Ghomizadeh in Iran. The provisional position for this spot measured from the image is: latitude 37.5 degrees north (planetographic), longitude (System 3) 248 degrees.
Just over 5 hours later, David Gray in the UK visually recorded a light spot approaching the p. limb. The provisional position for this spot measured from David’s drawing is: latitude of 37.5 degrees north, longitude (System 3) 29 degrees.
Saturn is well placed for observation before dawn and more observations are urgently required to confirm these features.
Mike Foulkes
BAA Saturn Section director.
12 December 2010
The first well-observed case has been reported of a large main-belt asteroid apparently exhibiting ‘comet-like’ behaviour.
Steve Larson of the Lunar and Planetary Laboratory, University of Arizona, has reported that images of the minor planet (596) taken on December 11.44-11.47 UT with the 0.68-m f/1.8 Schmidt telescope at Catalina show theobject to be in apparent outburst with a comet-like appearance, exhibiting a total V magnitude of about 13.4 and an envelope that extends 2′ north and 5′ west of the central condensation (CBET No.2583 issued December 12). Note that the predicted magnitude of this asteroid at the time of Steve’s observation is about 60% fainter than the observed value.
BAA member Peter Birtwhistle obtained images from Great Shefford Observatory between December 12.178-12.204 showing the presence of a large arc to the north and smaller arc to the south in a field 3′x3′ in size – See: http://www.birtwhistle.org/Gallery(596)Scheila.htm
(596) Scheila is a large asteroid (diameter ~113 km) situated in the outer regions of the Main Belt, having a dark surface (albedo = 0.038). A rotation period of 15.8 hours has been reported and from the amplitude of its lightcurve(0.09 mag) it must be relatively spherical in shape. In other words it is a very ordinary, rather typical asteroid with no special features. Likewise its orbit is definitely asteroidal in nature and not cometary.
It has been speculated that we have just witnessed the aftermath of a high-speed collision between (596) and a small, non-descript object, perhaps no more than a metre or two in size. The two conjoined arcs visible in Peter’s stacked image are reminiscent of the arc-shaped material of ‘Comet P/2010 A2′ imaged by the Hubble Space Telescope in January of this year – See: http://hubblesite.org/newscenter/archive/releases/2010/07/image/a/
For this latter case, it has now been shown that this phenomenon was not cometary but was indeed the result of a collision between two small bodies in the asteroid belt.
Further observations of the evolution of the ‘debris’, dust, etc. around (596) Scheila should make it possible to discriminate between the collisonal hypothesis and a cometary origin. My money is on the former. Indeed, high-resolution spectroscopy of the emitted cloud of material could provide a unique opportunity to probe the composition of an asteroid by analysing the nature of the expelled material. Let’s hope that an 8-metre or 10-metre class telescope will be put to work doing just this in the very near future.
Checks should also be made on images of (596) taken in the past to see whether an associated coma can be found at some other epoch. If such a coma were to have occurred in the past then this would demonstrate recurrent activity characteristic of a true comet.
One of the BAA Variable Star Section sister organisation, Variable Stars – South, headed by Dr. Tom Richards, have recently launched a project to attempt to find extra-solar planets around other stars from eclipse timings. This is a long term project but those equipped with a CCD camera on their telescope may care to look at the project details at www.variablestarssouth.org > Research Projects > SPADES.
Tom writes:
“We have now issued the third tranche of SPADES target systems, up to RA 7h and suitable for observation through February. That brings the total of targets for observing up to 22. Many are equatorial, making them suitable for our northern colleagues.
“We are hoping that many more observers with CCD experience will join this project. The basic approach to observing is just to get a good time series on an eclipse that’s going to occur close to your meridian, close to midnight – so you get a full eclipse profile. It’s a long-term project rather than night-after-night – wait until you get a suitably placed eclipse one night, and observe it.
“All information you need is on our www.variablestarssouth.org website. Research Projects > SPADES. There you will find a project specification, science case, and observing/reporting requirements. Linked you’ll find a table of data on the stars, and another table of comp star data. You can also download a data table for EB_min (from http://members.shaw.ca/bob.nelson/software1.htm) , which is the best way to find information on eclipses visible from your site.
“If you have any questions or want to discuss the project and your work, please note our website has a forum dedicated to this project.”
M42 in Orion
This week’s BAA Picture of the Week is of M42, the Orion Nebula, imaged by James Fraser on 2010 November 15.
100mm refractor with Canon 400d camera. 165s exposure at ISO 800.
@britastro