- Academic Departments(3)
- Calendars and Timekeeping(13)
- Data Archives(22)
- Eclipses, Occultations and Transits(15)
- Extrasolar Planets(14)
- Extraterrestrial Life(45)
- In the Arts(2)
- News and Media(14)
- Products and Services(339)
- Research Groups and Centers(25)
- Solar System(110)
- 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.
- Absolute Astronomy
- Facts and statistical information about planets, moons, constellations, stars, galaxies, and Messier objects.
- An Atlas of the Universe
- Contains 3D maps of the universe zooming out from the nearest stars to the scale of the galaxy and out to the surrounding superclusters and finally to the scale of the known universe.
- A Review of the Universe: Structures, Evolutions, Observations, and Theories
- A retired physicist surveys the entire extent of the universe touching upon phenomenon from the largest to the smallest size and covering the entire cosmic interval from past to present.
- Astronomy Today
- Information and articles on astronomy, space and related topics. Also features a friendly forum and a telescope buyer's FAQ page.
- Astronomy Online
- Gives overview of the solar system, the Milky Way galaxy, extrasolar planets, cosmology and astrophotography. Includes images, additional resources, and forums.
- Multi Unit Spectroscopic Explorer. A second generation integral field spectrograph for the VLT. Proposed to European Southern Observatory (ESO) by the Centre de Recherche Astronomique de Lyon (CRAL).
- Cosmos Portal
- Offers information on astronomy and space science including news, events, blogs, images, videos and links to other sites. It is written and compiled by experts.
- Astronomical Optical Interferometry
- The use of multiple telescopes to produce high resolution images - commonly used at most modern observatories. A literature review article.