Copyright 1992 by David A. Curry

Permission to use, copy, modify, distribute, and sell this software and its
documentation for any purpose is hereby granted without fee, provided that
the above copyright notice appear in all copies and that both that copyright
notice and this permission notice appear in supporting documentation.  The
author makes no representations about the suitability of this software for
any purpose.  It is provided "as is" without express or implied warranty.

------------------------------------------------------------------------------
							April, 1992

This is Version 1.0 of N9MSW XSAT, an X Window System based satellite
tracking program.  XSAT provides the following features:

	- On-screen or PostScript display of maps of each continent, the
	  United States, or the world.

	- On-screen or PostScript display of "ground track" information
	  placed over the maps, showing the path of the satellite.

	- On-screen or PostScript display of satellite visibility and
	  location centered on a particular city.

	- Interactive selection of the city from which to compute satellite
	  visibility information.

	- Interactive selection of the satellite to be tracked.

	- Interactive adjustment of simulation parameters such as start and
	  stop times, step time, and minimum satellite elevation.

The orbital calculations are done using the code written by Robert Berger
(N3EMO), and posted to comp.sources some time ago as "n3emo-orbit".

XSAT 1.0 has been compiled and tested on a Sun SPARCstation 1 running SunOS
4.1.1 and MIT X11R5.  It hasn't been tested on anything else, but if changes
need to be made on other systems, they should be minor.  Please send any
patches in "diff -c" output to the author at the address given below.

To install XSAT, do the following:

1. Edit the Imakefile and set the value of XSATLIBDIR to be the path of the
   directory in which to store XSAT's data files.  The data files require
   about 4MB of disk space.

2. Edit the "xsat.h" file and change any of the defaults you don't like.
   The defaults are fairly reasonable, and can be changed as X11 resources,
   so you probably won't need to change anything.

3. Build the Makefile and build the program:

	% xmkmf
	% make

4. Install the program and data files:

	% make install

5. Install the manual page:

	% make install.man

Notes on some of the data files:

lib/cities.info
	This file contains the names of cities the program knows about, and
	their latitude, longitude, and elevation.  There are about 350
	cities listed, but elevations are listed only for the cities in the
	United States.  I do not have a source for elevation information
	for international cities.  The latitude/longitude information for
	the non-US cities is also not as accurate as it could be; it came
	from the UUCP map database.

	Make sure your city is listed in this file; if not, you will have to
	select a nearby city.

	If you have elevation information for any of the cities listed, or
	better latitude/longitude information, or new cities not in the file,
	please send them to me and I will add them.  Please tell me your
	source for the information when you send it.

lib/map.*
	These are files of line segments (x1,y1) (x2,y2) for drawing the
	maps.  The files in the XSAT distribution are a massaged and
	combined version of the ones distributed by James Peterson of MCC.
	The original source for the data is the CIA World Data Bank, circa
	late 1980's.

lib/sattelites.doc
	A description of the NORAD two-line orbital element set format used
	by XSAT.

lib/satellites.info
	The NORAD two-line element sets for just about all the satellites up
	there.  This file is posted to the net in sci.space (or sci.space.news)
	every week or so; it is also available via anonymous FTP from the host
	blackbird.afit.af.mil in the directory pub/space, or can be obtained
	from the Celestial BBS, (513) 427-0674.

If you have comments, questions, or modifications for XSAT, please direct them
to the author.

Enjoy.

David A. Curry, N9MSW
Purdue University
Engineering Computer Network
1285 Electrical Engineering Building
West Lafayette, IN 47907
davy@ecn.purdue.edu