star charts with satellites

Robert Preston (rapr@med.pitt.edu)
Fri, 9 Dec 94 11:27:15 EST

In response to some of Ryan Rudnicki's questions:
For predicting satellite visibility and laser-printing maps 
using the Macintosh platform, the program "SkyChart2000 v2.2",
written by Tim DeBenedictis, is superb.  A demo version can
be obtained from Tim (timmyd@netcom.com) at no charge, but the
$30 (U.S.) complete version has additional interface features
that make it well worth the money, in my opinion.

The program takes as input text TLE listings (or fractions of
the list), for example, from T. Kelso's lists, and will make
"tracks" for as many satellites on the list as one wants at
the same time or separately.  Various projections of the sky
(spherical, mercator etc) at various magnifications can be
simply chosen by menu.  Supposedly, conjunctions between
objects can be searched automatically, but I haven't figured
out how to do that.  I've been using it only for Mir and 
Shuttle, using its animation feature (with time increment
user-selected from 1 sec to 10,000 years range) to simulate
the satellite tracks for the evening or next day or two.

Since planets and the sun and moon are shown true to size (at
the proper sky magnification setting), one can predict transits
of the moon or sun by any satellite, for high-power telescopic
viewing, if you have a telescope.  I have been able to catch
Mir (for about 300 milliseconds) in the half-degree-wide field
of a telescope low-power (80x) eyepiece, when Mir was in the
solar shadow of the Earth, but illuminated by moonlight.  So
I know the program draws charts accurately to within 1/2 degree
at least.

Robert Preston
rapr@med.pitt.edu