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From: nather@utastro.UUCP (Ed Nather)
Newsgroups: net.astro.expert,net.space,net.flame
Subject: Re: Re: Re: New orbit of Halley's comet
Message-ID: <22@utastro.UUCP>
Date: Mon, 1-Apr-85 01:02:36 EST
Article-I.D.: utastro.22
Posted: Mon Apr  1 01:02:36 1985
Date-Received: Wed, 3-Apr-85 02:07:30 EST
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Organization: U. Texas, Astronomy, Austin, TX
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The McDonald data, now reduced, agree with data from both Hawaii & Hale;
however, the Flagstaff data, with somewhat larger errors, still suggest
it can miss by a fair margin.  There is always a small but finite chance
some fault-line might be triggered into an earthquake, but no worse than that.

In the event of a grazing encounter with our atmosphere (still *very* 
subject to measurement error) artificial cyclonic activity could become
a serious problem but we don't know how to model that.  Impact is considered
highly unlikely in any event.  What is of far greater astronomical interest,
of course, is what caused the huge orbital perturbation in the first place. If,
as Burbidge suggested, it was caused by Nemesis, then Halley cannot be the
x-ray source found nearby -- it just is not massive enough to be a black hole.

If the data in hand can be refined (and new data obtained in a few weeks),
then we can say, with far greater assurance, whether Halley will pass on the
sunward side or not -- the spectroscopists hope so, naturally.  We *do* know
all observatories have been alerted to either possibility and are making their
plans accordingly.

Regardless of which side it passes on, it will be a spectacular show, but
its orbital inclination and high closing velocity give our instrumentalists a 
lot less time than we had hoped.  Even so, we expect we can have, at worst,
1 or 2 new daylight photometers ready to go.
:%s/^./& /
-- 
Ed Nather
Astronony Dept, U of Texas @ Austin
{allegra,ihnp4}!{noao,ut-sally}!utastro!nather