Newbie with questions/Macintosh sat tracking

DJLaszlo@aol.com
Sat, 21 Dec 1996 12:48:31 -0500

There are at least two good Shareware options for Mac users:

SkyChart 2000.  Old version, 2.2.1 was $28.  Will search for conjunctions,
eclipses, and can therefore be applied to look for passes of selected sats
near bright objects as you wish.  I think you would find the sky plots
adequate for most sat spotting without making special effort to find appulses
with bright objects.  Plots can be magnified for precise field mapping.
 Animation allows cool views of the motions of satellites in the night sky,
graphically contrasting sats in low Earth orbit vs Molniyas, geosynchs, GPS,
GLONASS, weather sats.  Several map projection options.  You can shut off the
stars and just watch sats.  Speed is adequate on an 040 Mac, and a zippy
Power PC version is available.  I like SkyChart for producing Mir maps for
schoolkids.  Also good for a quick chart of a comet path.  

Minuses:  A bit cumbersome for satellites.  Need to use a separate utility
(supplied) to perform a format conversion on NASA tles.  Magnitude
predictions are way off.  Plots do not indicate whether sat is illuminated
and visible, but you can look for a jump in the magnitude prediction.  Unless
you freeze the horizon, map rotation during a pass takes some getting used
to.  No fancy planet surfaces, but does show phase and a Lat/Long grid.
 Shows perspectives from anywhere in the solar system, and has an
interstellar travel simulator.    Demo version 2.5.2 on America Online.

I have used a beta version of 2.5, the current release, which is a big
improvement.  New version corrects the map rotation problem.  It accepts NASA
TLE elsets directly.  I will probably upgrade.   The price for either Mac or
Windows version is $34.95 as of mid-1996.  Please contact Southern Stars
Software for current pricing, ordering, and other product information at the
following address:

Southern Stars Software
12525 Saratoga Creek Drive
Saratoga, CA 95070
(408)-973-1016
SthnStars@aol.com


A demo version of SkyChart 2000.0 is available from a large number of on-line
sources, include Southern Stars Software's world wide web home page
(http://www.netsys.com/sthnstars).  


I use Orbitrack 2.1.5 a LOT to generate tables of predictions.  Reliably
identifies satellite visibility/disappearance into Earth's shadow.  Loads
data with minimum fuss, lifts TLE's from TEXT files without the need to edit
out leading and trailing text, a real timesaver.  Needs an FPU for decent
speed if you run more than a few satellites, or calculations for more than a
day or two.  Nice real time sat/Earth maps, with a ground view circle, and
ground track maps for any interval.  Distortion on sky plots around the
celestial poles, due to using Mercator projection, and sky plots do not
identify the part of the track in shadow.  No magnitude predictions.  A
practical tool if you want to hunt many sats, or if you want to watch a real
time plot of Mir over an Earth map.  Fun to watch the ballet of a NOSS trio
on a magnified map.  $10 to register download; $20 to get a floppy in the
mail with hard copy manual.  On many online services.  Good support from Bill
Bard, who is a SeeSat-L contributor.  We need to ask Bill if there will be a
Power PC version.

Source:  Version 2.1.5 available, with manual, in Astro's Archives on AOL.
Author Bill Bard is at:   bekdev@gte.net (BEK Developers)

Until Mac software appears with accurate magnitude values, you will probably
want to get some experience with Mike McCants' Quicksat (DOS).  I would
expect Quicksat to be fast enough to be practical with a PC emulator on a
Mac.  I once tried a demo version of SoftPC, but the demo lacked the math
functions to run Quicksat.  It runs fine with an Orange PC 486 card.
 Quicksat efficiently gives tables of satellite culminations, and if
culmination is in shadow, the maximum elevation when illuminated.  

Let me know if you have more questions.  Cheers, Dan Laszlo
    djlaszlo@aol.com