SkyORB

SkyOrb is a tool for Mac OS X Leopard similar to Celestia and Stellarium that lets you explore the night sky without leaving your house.

Specifically, SkyOrb is a 3D planetarium that shows the real-time orbits of the different celestial bodies that make up the solar system (mainly the planets and their respective satellites) and also offers the possibility to view a virtual representation of the sky, including constellations, from any place on earth.

SkyOrb also includes a small database with 35 different types of spacial phenomenons that have occurred or are going to occur. You can see simulations of total and partial eclipses of the sun and moon, as well as planet alignment, cover, transit, elongation, and opposition.