The official public beta of WorldWide Telescope, is now available at: http://www.worldwidetelescope.org.
WorldWide Telescope comes from Microsoft Research and is a rich Web application that brings together imagery from the best ground- and space-based observatories across the world to allow people to easily explore the night sky through their computers.
The application itself is a blend of software and Web 2.0 services created with the Microsoft high-performance Visual Experience Engine, which allows seamless panning and zooming around the heavens with rich image environments. WorldWide Telescope stitches together terabytes of high-resolution images of celestial bodies and displays them in a way that relates to their actual position in the sky. People can freely browse through the solar system, galaxy and beyond, or take advantage of a growing number of guided tours of the sky hosted by astronomers and educators at major universities and planetariums.