Expert: Courtney Seligman - 12/4/2008

Question
Hello Professor Seligman -

In a previous question on azimuth of celestial bodies, you mentioned that there are many free online planetariums. Can you recommend any? I did some searching and found so many - some free, others expensive.

I am particularly interested in Earth-Sun motion, position, angles, azimuth.

Thanks again for all your help.
Bill
Olympia WA  

Answer
Prior to answering your earlier question, I hadn't looked at online planetarium software in any detail; I just knew that there were many such programs available. Since then, I've been looking at a few. One that I've downloaded but haven't had a chance to try out is the World Wide Telescope (http://www.worldwidetelescope.org). I'm not sure it's "planetarium" software so much as a library of images taken by various telescopes in space and on Earth, but it looks very interesting, and I'm looking forward to exploring its possibilities once I'm done with finals.

Another one is Stellarium (http://www.stellarium.org). It is true planetarium software, actually being used at some real planetariums, so it might be more what you're looking for. Its interface isn't as intuitive as I'd have hoped, but it looks very promising.

Courtney Seligman