Astronomy

• 50 Interesting Facts about Mars
• Astronomical Almanac Online -- "is a joint publication of the U. S. Nautical Almanac Office, United States Naval Observatory (USNO), in the United States and Her Majesty's Nautical Almanac Office (HMNAO), United Kingdom Hydrographic Office (UKHO), in the United Kingdom. The printed version contains precise ephemerides of the Sun, Moon, planets, and satellites, data for eclipses and other astronomical phenomena for a given year, and serves as a world-wide standard for such information. The online version extends the printed version by providing data best presented in machine-readable form."
• Astronomy Media Player -- "A selection of the best astronomy podcasts from around the world." Includes astronomy courses, observations of the night sky, "ask an astronomer" podcasts, and podcasts from observatories and space agencies.
• Astronomy Picture of the Day: complete with a brief explanation by an astronomer.
• AstroWeb: searchable astronomy, astrophysics database.
• Bradford Robotic Telescope
• Great Images in Nasa --over a thousand high-quality photos, keyword or browse searchable.
• High Redshift Supernova -- images too.
• HubbleSite--the Space Telescope Science Institute's images from the Hubble spacecraft.
• Imagine the Universe Dictionary-- a dictionary of astronomy and astrophysics from NASA's astronomy education page
• Infrared Astronomy--from NASA's Infrared Processing and Analysis Center, history, backgrounds, images, and current projects in infrared astronomy.
• Mars Images -- from the famed rover
• N-Body Shop -- movie files of astronomical events.
• NASA Planetary Science Research Discoveries--is a site devoted to discoveries being made in planetary and space sciences through NASA-sponsored research. It contains feature stories, news links, a comprehensive archive of articles, glossary, search engine, subscription service, and comments page.
• The Nine Planets : A Multimedia Tour of the Solar System
• Official String Theory Web Page
• Peoria Astronomical Society--info on star names, black holes, constellations, and a good set of links to other astronomy sites.
• Physics and Astronomy reference -- "a comprehensive physics and astronomy online education, research and reference web site."
• Planetary Photojournal -- from the folks at JPL
• Skylab Project -- includes the history, goals, images, and facts about the first 100 manned space flights.
• Sky Online--Sky-at-a-Glance tells you what astronomical events to be on the lookout for with your telescope. (And if you don't have a telescope, the "Backyard Astronomer" section will help you choose one).
• Sloan Digital Sky Survey -- the most ambitious astronomical survey project undertaken.  This project will map in detail one-quarter of the entire sky, determining positions of more than 100 million celestial objects.
• U.S. Naval Observatory -- sunrise/sunset calculations, the "Sky This Week", links to their library and other resources.
• World Wide Telescope -- with input from Microsoft, the site requires adobe flash player and that Java be enabled, but it is worth it! "sets a new standard in three-dimensional representation of vast amounts data plucked from space telescopes, the ease of navigation, the visual experience and features like guided tours narrated by experts."