Microsoft Worldwide Telescope 2.1.08.1
http://www.worldwidetelescope.org/
If you love astronomy, then I'm sure you've checked out Stellarium, Celestia, and of course, Google Earth (with its 'Sky' feature). If you like these apps, but were wanting a little more in-depth science/geeky goodness...then you'll LOVE Microsoft Worldwide Telescope.
Worldwide Telescope falls into the area of "Microsoft Research" (think Google Labs), so it is one of those cool projects that isn't part of the mainstream Microsoft product profile.
From Microsoft's web-site:
The WorldWide Telescope (WWT) is a Web 2.0 visualization software environment that enables your computer to function as a virtual telescope—bringing together imagery from the best ground and space-based telescopes in the world for a seamless exploration of the universe.
WWT is much more than your typical planetarium software in that it gives you actual photographs and readings from the entire night sky. I.e., you could view actual indexed Hubble/radio/infrared imagery of an assortment of cataloged items.
A very cool (and probably the end purpose of the software) feature is the ability to go on "virtual tours" with narration from field experts - a little more interactive than the tour feature in Google Earth, which makes this an invaluable resource for educators and students alike.
Like Google Earth, you can also focus in on the Earth and zoom in using Microsoft Virtual Earth imagery (including street view).
What I thought was really cool was the ability (could not test this) for you to connect a supported telescope and use WWT to direct it to the object selected on the screen - many higher-end Meade telescopes have this ability with other commercial and free planetarium programs.
As you can see, the interface is consistent with the current Microsoft interface style (Windows Media Player 11, for example)...which makes it very easy to navigate, without letting the menu and commands get in your way.
You can browse a collection of objects by clicking on the 'Explore' tab at the top...upon which, you will be presented with a series of categories to go through. For example, you can look at constellations, Hubble, Chandra, Messier catalog items, Solar System objects and your own customized collection (and more).
I can't see this replacing Google Earth entirely, but I will say that as far as viewing stellar objects, this is a far more useful program. If you want to view Earth-based objects, then you should stick with Google Earth.
