Ordinary Meeting, 2006 January 25

The January Sky

Mr Mobberley opened by noting that, during the meeting, Saturn and its rings would occult the mag 7.9 star BY Cancri, although the planet would be at a low altitude during the interesting early passage behind the rings. He announced that Hazel McGee had discovered a Near Earth Object (2006 AT3) by downloading and checking thousands of CCD frames from the Kitt Peak Spacewatch telescope. This was the third UK success using this public outreach facility, the first two being by Ken Pavitt and Roger Dymock. Moving on to planets, Mr Mobberley explained that Mercury would make a favourable appearance in the evening sky around Feb 24^th, and he showed some fine crescent Venus shots taken in December by BAA member David Arditti. Venus was now moving into the evening sky. Despite Mars still being below 10 arc-seconds in size Damian Peach was continuing to secure high resolution images of the red planet. Saturn was especially well placed in the January evening sky and Mr Mobberley urged members to watch the ringed planet on opposition night, in two days time, when the rings should appear very bright due to the Seeliger effect. Saturn would be travelling through the lower half of the Beehive Cluster over the coming weeks which should make a nice photo-opportunity. Staying with Saturn Mr Mobberley showed some recent spectacular Cassini images, including a shot of faint dust above the ring plane which might account for the spokes seen in the Voyager images of the 1970s. He also showed new Cassini images of Rhea and Dione. Jupiter was now observable again in the dawn sky, although it was painfully low down. However, again, David Arditti had persevered with the planet from his Edgeware location and obtained some images in the last few weeks. In Japan Hideo Einaga had discovered a new mid-SEB outbreak of white spots which was a development well worth following. Moving on to comets, a new one had been picked up by the ASAS patrol team and had been named after its discoverer Grzegorz Pojmanski, of Warsaw University. 2006 A1 (Pojmanski) had a similar orbital path to that of the famous Comet Bennett in 1970 but, unlike Bennett, would most probably not be a spectacular object by the time it came into northern skies. Comet 2005 E2 (McNaught) was still reasonably bright, at around magnitude 10, but very low in the SSW evening sky. A Centaur asteroid, similar to the famous object 95P/Chiron had been seen with a coma recently and thus would almost certainly be designated as a periodic comet. The object, 2000 EC98, was currently magnitude 14 in Virgo, despite being 13 AU from the Sun. Mr Mobberley drew members attention to the comet 73P Schwassmann-Wachmann, currently 16^th mag and with an 18^th mag fragment accompanying the comet. From the audience Mr Shanklin pointed out that this comet would be making a very close passage to the Earth in May, and some estimates predicted the largest fragment could be 6^th mag, but a highly diffuse one degree across, in our skies at that time. Comet 2003 WT42 was also a CCD target in Ursa Major and Mr Mobberley expected 41P Tuttle-Giacobini-Kresak to rapidly brighten into amateur CCD range in the next month or two. Moving on to Supernovae, Mr Mobberley was pleased to announce that three more UK supernovae had been discovered since the last meeting, two by Tom Boles and one by Mark Armstrong. Tom had bagged the prestigious SN 2006A, the first supernova of the New Year, and was now only five away from his 100^th supernova. Only two other individuals had their names associated with more supernovae on the IAU listings, namely the legendary (if abrasive) Fritz Zwicky and the US amateur Tim Puckett, who had just overtaken Zwicky's total of 123 discoveries. Mr Mobberley reminded members that the BAA and Mark Kidger were very keen on magnitude estimates of the active galaxy and suspected binary black hole candidate OJ 287 which might flare up this year and was situated near to the Beehive Cluster, not far from Saturn at the current time. He also reminded members that the Moon would be very favourably placed in our skies at the end of the first week in February, and throughout the year, attaining a declination of +28 degrees once a month. Moving on to asteroids, Mr Mobberley showed recent images by Maurice Gavin, of Juno and Vesta, as well as an image and light curve of the BAA's own asteroid 4522 Britastra, secured by the President, Richard Miles. He also pointed out that asteroid 3697 Guyhurst would reach opposition around the start of April. Mr Mobberley then showed some results from last July's Charon Occultation in which a team from Paris had measured the diameter of Pluto's satellite as roughly 604 kms. As far as asteroid occultations were concerned, an event was actually taking place during the BAA meeting, that involving 3939 Huruhuta, and there were a number of other potential events over the next week. An occultation of a 15^th mag star, by the trans-Neptunian body Varuna, on Dec 31^st, had been clouded out. Once again though, Andrew Elliott had been successful, recording an occultation by 134 Sophrosyne on Dec 27^th. Finally, Mr Mobberley looked ahead to March when there would be a deep penumbral eclipse of the moon and a partial eclipse of the Sun. Many BAA members were heading for the region of totality which would cross Libya, the Mediterranean and Turkey on March 29^th.

Following the applause, the President invited Mr Chris Lintott of University College London to present the evening's second talk. Mr Lintott would be a familiar face to many members from his frequent appearances on the BBC's Sky at Night; on this occasion he would be talking about recent developments in cosmology.