Platform: Windows XP
Number of downloads: 8386
Celestia offers a 3D simulation of the galaxy and beyond. Everything is simulated in real time, meaning that what you see is actually happening right now. Time can be speeded up, slowed down or even reversed, giving you a glimpse into the past or the future.
A demo can be run for a whistle-stop tour of the immediate solar system, including the Earth, Saturn, the Sun and other phenomenon such as star formations and gas clouds. Snippets of information appear as you travel.
To get more involved, you need to take control. Using mouse and keyboard commands you can float through the galaxy at your will. Find something interesting and it can be zoomed in on, followed on its voyage across the galaxy and much more.
A Tour facility lets you jump directly to any element - star, planet, asteroid or comet - and displays brief related data on-screen.
More detailed information on an object can be displayed in a web page, acting as a starting point for further study.
Screen grabs or movies can be saved at any point - great for use as a teaching aid.
This latest release adds Eclipse shadow rendering, orbital calculations for major moons, and phase lock and chase camera modes. This means you can now view eclipses on Earth, Saturn and Uranus, and view comets, asteroids and spacecraft on the move. Various bugs have also been fixed.