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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  (:-)