Celestia is a cross-platform OpenGL space simulator. By using state-of-the-art OpenGL it provides an accurate, comprehensive, educational, and fun space simulation for astronomers and casual users alike.

Celestia/GTK: a front-end designed to require the minimum number of libraries for the maximum number of features provided by the OpenGL core.

Celestia/GNOME: an expanded Celestia/GTK with GNOME integration features such as GConf and URL handling.