Absolute Astronomy
Facts and statistical information about planets, moons, constellations, stars, galaxies, and Messier objects.
http://www.absoluteastronomy.com/
Astronomical Applications Department, U.S. Naval Observatory
Computes the position, brightness, and other observable characteristics of celestial bodies, as well as the circumstances of astronomical phenomena. Includes information on calendars and related topics.
http://aa.usno.navy.mil/
Astronomy Net
Resources, searchable forums and searchable lists of organizations providing astronomy services.
http://www.astronomy.net/
