Celestia: A 3D Space Simulator
	Celestia is a free real-time space simulation that lets you experience our universe in three dimensions. Unlike most planetarium software, Celestia doesn't confine you to the surface of the Earth. You can travel throughout the solar system, to any of over 100,000 stars, or even beyond the galaxy. All travel in Celestia is seamless; the exponential zoom feature lets you explore space across a huge range of scales, from galaxy clusters down to spacecraft only a few meters across. A 'point-and-goto' interface makes it simple to navigate through the universe to the object you want to visit.
http://www.shatters.net/celestia/index.html

Open Universe: A Free Space Simulator
	What is Open Universe? Strictly spoken it's a piece of software, simulating the Solar System's bodies in 3D on your Windows or Linux PC (will work in most *NIX's as well). In difference to quite a few other programs it does so in realtime. Meaning you can view all the planets, moons and spaceships move along their paths, trace them, follow them, orbit them and even control them (time and spaceship contol). And you won't have to fight your way through hordes of green, slimey and one-eyed aliens for that ;-)
http://openuniverse.sourceforge.net

Earth 3D visualization program
	Earth3D is a program that visualizes the earth in realtime in a 3D view. It uses data from NASA , USGS , the CIA and the city of Osnabr�ck . I would like to thank these organisations to allow me to use their data! The program is available as binary for Linux, MacOS X and Windows under the GPL license. The program's features are viewing the earth as a whole zooming in until countries, cities and even single houses become visible (in areas where the necessary map resolution is available) embedding external data like current earthquake positions or cloud data
http://www.earth3d.org/

Sky Chart: Free program to draw sky charts
	This program enables you to draw sky charts, making use of the data in 16 catalogs of stars and nebulae. In addition the position of planets, asteroids and comets are shown. The purpose of this program is to prepare different sky maps for a particular observation. A large number of parameters help you to choose specifically or automatically which catalogs to use, the colour and the dimension of stars and nebulae, the representation of planets, the display of labels and coordinate grids, the superposition of pictures, the condition of visibility and more. All these features make this celestial atlas more complete than a conventional planetarium.
http://www.ap-i.net/skychart/index.php

Operating Systems Key

	Microsoft Windows		Linux Source Code
	RPM for RedHat Linux and Fedora Core		RPM for SuSE Linux
	RPM for Mandrake Linux		Slackware Linux Package (tgz)
	Debian Linux Package (deb)		BSD (FreeBSD, NetBSD, OpenBSD)
	Solaris		Mac OS

Note for UNIX systems.

If a pre-built package of an application is not available for your Linux distribution or your UNIX variant most applications can be built from the Linux source code. Consult the applications documentation, which will contain instructions for building the application from source. RPM's of applications may by available from other sources.