SPA Comet News, February 2001

Comet 1999 T1 (McNaught-Hartley) is currently an easy binocular object of 8th magnitude in Hercules. The trouble is, this puts it in the morning sky and few observers are willing to get up to view it, although the sky is still dark at 6 am. The comet is well condensed, thus making it easier to see, even from city skies. I have been able to view it from my back garden in central Cambridge using 20x80 binoculars. It is now past maximum brightness, but its motion northwards slowly brings it into view in the evening sky and by the end of the month it will be visible by 10 pm. By then, however, it will have faded to 9th magnitude and may require a small telescope to view it.

The best plan to locate a comet is to prepare a finder chart in advance using one of the many planetarium programs currently available. I use Megastar, with a 15 x 10° field and a limiting magnitude of 9 for the finder chart and then a more detailed chart on a larger scale showing stars down to a few magnitudes below the expected magnitude of the comet. I then use the pair of charts to star hop to the comet. Once you've found the comet you should try and make a full observation and there is lots of helpful advice on my web page at http://www.ast.cam.ac.uk/~jds. If you use the chart and don't have access to reference magnitudes, identify the stars you use on the printout using letters A, B, C, D etc and post me the chart along with your estimate in standard variable star format (eg A (1) V (2) B) when you submit the observation. Do not use any of the stars shown as variable; these are circled and often identified specifically.

Michael Oates has continued to search the SOHO LASCO database with considerable success and has now discovered 110 SOHO comets, which is over 1/3 of the SOHO total of 292. SOHO also imaged the recent surprise discovery of Utsunomiya and Jones, though it was not a prominent object. Albert Jones, from New Zealand, made his discovery whilst making a variable star observation and it was then linked to an earlier discovery from Japan. I was lucky enough to be in the Southern Hemisphere at the time, though I had to contend with the bright twilight skies of the sub Antarctic. I did manage to glimpse the comet a couple of times in the deep twilight using 7x50 binoculars. Albert is at 80 years old, the oldest ever comet discoverer and this is actually his second accidental comet discovery; the first took place in 1946!

Looking to the future a discovery by LINEAR at the end of last year promises to be an interesting object in the autumn, though early predictions are often wide of the mark. Comet 2000 WM1 should come within range of most SPA members in October, and it could reach naked eye brightness in November. Its track takes it through Perseus in October and early November, then down through Aries, Pisces and Cetus. It plunges south quite rapidly and we will loose it by mid December, though Southern Hemisphere observers will see it at its best when it reaches perihelion in January. It returns to our skies in spring 2002 as a binocular object.

Updated 2001 February 9

Published by Jon Shanklin - jds@ast.cam.ac.uk