TechBlog

.. The free space simulation that lets you explore our universe in three dimensions. Celestia runs on Windows, Linux, and Mac OS X.

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 movement 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.
Celestia is expandable. Celestia comes with a large catalog of stars, galaxies, planets, moons, asteroids, comets, and spacecraft. If that’s not enough, you can download dozens of easy to install add-ons with more objects.

Download:

# Windows
The Windows package of Celestia is a self-extracting archive; download it to your computer and then run it.

# Mac OS X
The Mac OS X package is a disk image. Download it to your computer, double click it, and follow the instructions in the README.

# Linux (x86)
If you are running Linux, you should check first with your distribution; there is a good chance that the package is available to you in the format best suited to your installation. A pre-compiled 32-bit version is provided in the autopackage format. It should run on any distribution that has OpenGL and GTK+ 2.6.

# Source Code
Celestia is an open-source project. As such, its source code is provided and is freely modifiable and redistributable as per the GNU Public License. Installation instructions are provided in the INSTALL file.

Celestia 1.4.1 User’s Guide
by Frank Gregorio

English MS Word document (zipped) or PDF

German MS Word document or PDF file (zipped)
German translation by Ulrich “Adirondack” Dickmann

Romanian MS word document (zipped)
Romanian translation by MindToAsk

French MS word document or PDF file (zipped)
French translation of 1.3.1 guide by Jean Anglade

FAQ
There’s no official FAQ for Celestia yet; however, Selden Ball maintains a list of frequently asked questions here on the Celestia forum.

Additional Documentation

Please see the documentation page at The Celestia Motherlode for a comprehensive list of documentation available for Celestia. In addition to documentation for Celestia users, there are many files of interest to people who want extend Celestia by creating add-ons and scripts.