The program has a rigorous and very scientific approach, calculations and the images beeing the actualized in accordance with discoveries, as well beeing also a pleasure to the eyes.
The aim of this site is to gather the maximum of informations, tips or addons for the program. As my connection isn't huge (according to the hours, you may experience some slowdowns), I advise you to download the large add-ons (more than 5 Mb) on the sites indicated at the links; stille better, you can use emule. As regards the small programs, small add-ons, help yourself, it should be quick enough. The site is permanently under construction, I try to follow the news, therefore do not hesitate to come back often ;-)
Celestia is a completely incredible simulator spacial, making it possible to travel in the solar system, the Milky Way and even in the universe very easily. During this exploration, one discovers real planets (y.c. the planets exosolaires), but such imaginary (for the science fiction amateurs).
Thus, one can see with exact data, missions like Cassini, Voyager, Hubble, etc, but also the Dark Star of the Empire. Textures of planets are photographs taken by the probes, the telescopes, and correspond to reality; one could discover what Cassini sees when bringing closer to Jupiter, as if one was walking around the bridge of a satellite bringing near the jovians moons.