Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site utastro.UUCP Path: utzoo!watmath!clyde!bonnie!akgua!whuxlm!harpo!decvax!genrad!panda!talcott!harvard!seismo!ut-sally!utastro!anita From: anita@utastro.UUCP (Anita Cochran) Newsgroups: net.astro Subject: Re: Pleiades, Meteors, Comet Halley Message-ID: <585@utastro.UUCP> Date: Wed, 21-Aug-85 21:42:35 EDT Article-I.D.: utastro.585 Posted: Wed Aug 21 21:42:35 1985 Date-Received: Sun, 25-Aug-85 01:29:12 EDT References: <1428@cbosgd.UUCP> <473@bbncc5.UUCP> Organization: U. Texas, Astronomy, Austin, TX Lines: 34 > [] > > This past weekend, attendees of Stellafane at Springfield, VT, were > treated to two sightings of Halley's Comet, believed to be the fifth > and sixth thus far. (in this apparition :-) This was achieved with > large telescopes, in the 24" range, under pretty good conditions. The > estimated magnitude now is about 14, so it would probably be a few > more weeks before 8-12" telescopes will find it. But now may be the > time to start trying. > > /jr We observed comet Halley last week but with a much larger telescope -- the 2.7 m (107 inch) at McDonald Observatory. When the comet came out of the sun in August, it was "recovered" by J. Gibson (Palomar), R. West (European Southern Observatory) and T. Seki (Geisei). Their measured magnitudes were from 16.5 on July 19 to 16 on August 4. Together, they made 10 observations. When we observed Halley last week, it was probably 15.5 to 16 mag and diffuse (very weak central condensation). This magnitude is well out of the range of a 12 inch telescope and is 2 magnitudes FAINTER than the predictions. (Note that Stellafane observers do not have the fifth and sixth sightings this apparition but for such small telescopes, their sightings are commendable. We hope they are contributing to the International Halley Watch Amateur net.) The faint magnitude does not bode well for this being a spectacular trip for Halley. -- Anita Cochran uucp: {noao, ut-sally, ut-ngp}!utastro!anita or seismo!ut-sally!utastro!anita arpa: anita%utastro@UTEXAS.ARPA snail: Astronomy Department The University of Texas at Austin Austin, TX 78712 at&t: (512) 471-4461