A space travel simulator lets you travel throughout the solar system even beyond the galaxy.
Pros & Cons:
Celestia is a space travel simulator. You can travel throughout the solar system, to any of over 100,000 stars, or even beyond the galaxy. There are add ins to expand the catalogs and images of comets, stars, solar system objects, and deep space objects. You can even add in fictional objects such as Star Wars, Star Trek, Babylon 5, etc.
I feel this is a fun way to view many of the objects themselves. There are images of many solar system objects, e.g. Deimos and Ceres.
As this is a simulator and not a planetarium program, Celestia does not indicate constellations, have telescope controls, or have a method for pointing to a specific location, e.g. RA 02:31:49.09 dec +89:15:50.8. (Not intended as a criticism—just an observation.)
A portable version of this program is available here.
Celestia was reviewed by Gizmos Freeware on based on version 1.6.0.