What is better than a telescope as a Christmas gift for that cousin of yours who is crazy about astronomy or the Milky Way? Especially when you are low on budget this month… The link to a free and open source space simulator should do the trick nicely. Celestia allows visitors to witness exciting celestial events which happened in the past or will happen in the future. It is available for download on Windows, Mac OS X, and Linux.
There are many cool features in Celestia. Oe special feature is the eclipse finder which simulates solar and lunar eclipses on any planet including Earth. These simulations can be viewed in real time (which may take years!) or sped up. In addition , by entering the coordinates of a specific spot on earth, you can bring the night sky to your computer screen and pretend that you’re seeing it from your backyard. If this is not enough, Celestia Motherlode provides add-ons of additional celestial bodies and spacecraft as well as textures which provide a richer experience of planet surfaces and the star systems. This would make interesting teaching material for a basic astronomy or science class. And it would thrill young or old people no end who have an interest in astronomy by bringing the planetarium onto their computer screen.
Screen shot: The 1989 flyby of Neptune by Voyager 2–last stop before leaving the solar system