Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10 6/4/83; site PSUVM.BITNET Path: utzoo!watmath!clyde!bonnie!akgua!psuvax1!psuvm!gms From: GMS@PSUVM.BITNET Newsgroups: net.astro Subject: re: Halley's Comet Message-ID: <1514GMS@PSUVM> Date: Tue, 15-Jan-85 22:01:04 EST Article-I.D.: PSUVM.1514GMS Posted: Tue Jan 15 22:01:04 1985 Date-Received: Fri, 18-Jan-85 00:44:45 EST Lines: 76 An excellent article regarding where and when to view Halley's Comet is the following: "A User's Guide to Halley's Comet" Dennis DiCicco, Sky and Telescope, September, 1983, pp 211-212 The following information is mostly gleaned from that article. Halley's comet will be visible during two periods of time extending before and after perihelion. (The closest point in its orbit to the sun, when it is essentially unobservable this time) These periods are from about September 1 to November 1 1985, and April 1 to June 1 1986. As for exactly where to look, that will depend on when you are looking. Pick up an issue or two of either 'Sky and Telescope' or 'Astronomy' magazine about a month or two ahead of time. They typically publish maps. Otherwise you can get a copy of the "Observer's Handbook 1985" from the Royal Astronomy Society of Canada (124 Merton St., Toronto Canada, 1979), they will undoubtedly publish the coordinates and a map or two. A number of factors control how it will appear. Those you can't do anything about include : - the angles and circumstances of the comet's orbit with respect to the Earth's orbit - how much of the solid matter in the nucleus of the comet is released into the ion and dust tails Factors you can do something about include: - generally the more south you are the better a view you will have during the post-perihelion encounter, which coincidentally is often the best time to observe a comet - getting away from light pollution, air pollution and fog will greatly improve your view, a mountaintop at least 100 miles from a major city is best, but anywhere not in heavy light pollution should be possible. It would be worthwhile to drive 20 miles to get away from the lights. To sum it all up, for Northern Hemisphere viewers, the best time is the pre-perihelion encounter. The best days are November 15 - 18 when the nucleus of the comet is passing just below the Pleiades star cluster in Taurus. (The tiny dipper just about overhead at end of evening twilight about this time of year) The Moon will be new on Nov 12'th so for at least a few days, weather permitting, it should be well placed for observation. Best bet is a good set of wide-angle binoculars and a very dark sky. I will be observing from Black Moshannon Mountain in Pennsykvania, anyone passing through or living near this area is welcome to join me. (reply via email) Happy observing! "Waited 31 years for this!" ------------------------------------------------------------------------------ Gerry Santoro Microcomputer Information and Support Center GMS @ PSUVM (bitnet) Penn State University !psuvax1!santoro (UUCP) 101 Computer Building santoro @ penn-state (CSNET) University Park, PA 16802 (814) 863-4356 - Member in good standing (I hope) of Amateur Astronomers Association of Pittsburgh - Leader of Penn State Eclipse Expedition - May, 1984 (:-)