From: utzoo!decvax!cca!Lynn.ES@PARC-MAXC@sri-unix
Newsgroups: net.space
Title: Re:
Article-I.D.: sri-unix.1613
Posted: Wed Jun  2 16:10:58 1982
Received: Fri Jun  4 05:44:27 1982

The chemical content of any given comet determines how it forms a head and
tail at various temperatures (and therefore at various distances from the sun).  So
the first time a comet is observed, we are taking a wild stab when we predict its
behavior.  Kahoutek was a first timer.  Halley's is not; it was recorded as having
been seen at most of its appearances for 2000 years.  There is little doubt that
Halley's will look spectacular under the proper viewing conditions.  That does
not include any metropolitan areas where you cannot see even one tenth of the
stars because of lights and polution.  It also does not, for this particular passage,
include northerly latitudes where the geometry of earth/sun/comet will keep
much of the spectacular time in local twilight or daylight.  Go south and away
from the cities, and excepting only for cloudy weather, you can be guaranteed a
spectacular comet.  

/Don Lynn

PS - Scientifically, Kahoutek was spectacular, because it was discovered early
and so allowed a long period of data gathering, even though it did not end up
nearly as bright as predicted.