Star Points for April, 2002; by Curtis Roelle Another Spring Comet for Sky Watchers Once again we have a decent Spring comet in our evening sky. Although it's not going to put on a show anything like Comet Hyakutake in 1996 or Comet Hale-Bopp in 1997, Comet Ikeya-Zhang is a beautiful site in a simple pair of binoculars. Later in this article we'll discuss how to find the comet in the night sky and where you can go to for more information. As the name suggests Comet Ikeya-Zhang was co-discovered by Japanese and Chinese observers that were first to see the comet on February 1. Kaoru Ikeya of Japan is a veteran comet hunter best known for his 1965 discovery of the bright sungrazer Comet Ikeya- Seki. This latest comet was the sixth cometary discovery for the 58 year old. This was Daqing Zhang's first comet. The Smithsonian Astrophysical Observatory at Cambridge, MA has concluded that Comet Ikeya-Zhang is a returning comet first discovered on February 3, 1661, only 50-odd years following the invention of the telescope. The astronomer Hevelius described the comet of 1661 as having "multiple structure in the nucleus" According to "Comets: A Descriptive Catalog" by Gary W. Kronk. I've been able to view the bright head of the comet as it reached naked eye brightness. In 10x50 binoculars it has a very straight pearly colored tail. In a telescope with a mirror 0.5 meters in diameter (20 inches) the head and its surrounding coma region had a distinctive greenish tint. The comet is visible low in the northwest in deepening twilight. If you remembered to set your clock ahead, the comet should be about 11 degrees above the northwest horizon around 08:00 p.m. EDT. this evening. The width across the knuckles of your fist at the end of an outstretched hand is about 10 degrees. The first step to finding the comet is to go somewhere that it is dark and with no obstructions to the northwest. It is at times like these that it can suddenly dawn on you what astronomers mean when they are talking about "light pollution." That neighbor's light aimed at your back yard may very well prevent you and your family from seeing this wonderful spectacle of nature. If necessary, kindly ask your neighbor to turn off their light. Invite them out to join you. If necessary travel outside of town, to the northwest preferably. Once you've found a good site it's time to start looking for the comet. The best way to find it without a star chart is to begin slowly sweeping along the horizon from one side to another with your binoculars while facing northwest. Then raise them about half a field width and slowly scan back the other way keeping them parallel to the horizon. As you sweep you'll notice stars moving through the field. Eventually though you'll find one that looks different than the others because it has a tail. That is the comet. Luckily, the comet is also becoming visible in the morning sky! Early risers up at 05:30 a.m. will see the comet at an altitude of 16 degrees in the northeast. Just face northeast and repeat the binocular directions given above for locating the comet. If you have a tripod adapter for your binoculars you might want to use it. That way once you have found it you can share your "discovery" with others. If you would like to see a finder chart and have web access, try this page at Sky & Telescope magazine's web site: http://skyandtelescope.com/observing/objects/comets/article_477_1.asp. The web site also has celestial coordinates for every other day if you are interested in plotting the comet's course on a star chart. At mid month the comet continues getting lower in the evening sky each night while the sky stays brighter longer. By 08:45 p.m. EDT on April 15 the comet has moved to the north-northwest sky and only about eight degrees up. You'll have more luck and better viewing catching it in the morning sky. At 5:00 a.m. EDT the comet is up a whopping 30 degrees in the northeast. By 5:30 a.m. it has climbed to 35 degrees, however the twilight sky will be rapidly brightening. Drop me an e-mail if you see it. I would enjoy reading about your observation.