American Astronomical Society (AAS)
Established 1899, AAS is the major professional organization in North America for astronomers, other scientists and individuals interested in astronomy.
www.aas.org Details

Antique Telescope Society
An international organization of colleagues interested in antique astronomical telescopes, books, binoculars, and related materials.
www.irhino.com Details

Association of Lunar & Planetary Observers

www.lpl.arizona.edu Details

Astronomical Society of the Pacific
Disseminates astronomical information. The ASP has become the largest general astronomy society in the world, with members from over 70 nations.
www.astrosociety.org Details

European Association for Astronomy Education
Improves and promotes astronomical education at all levels in all institutions involved in teaching astronomy in Europe. Contains membership information, the group's history, news, newsletters and projects.
www.algonet.se Details

European Astronomical Society (EAS)
An association founded under the Swiss Civil Code in 1990. Its purpose is to contribute to and promote the advancement of astronomy in Europe.
www.iap.fr Details

International Association of Geodesy
Member information, meeting announcements, publications and reports, awards, and links to related sites.
www.gfy.ku.dk Details

International Earth Rotation Service (IERS)
Works to maintain the International Celestial Reference System and Frame, and the International Terrestrial Reference System and Frame, and to provide timely and accurate data on the Earth's orientation for current use and long-term studies. Site describes the group's structure and function.
hpiers.obspm.fr Details

International Occultation Timing Association (IOTA)
was established to encourage and facilitate the observation of occultations and eclipses. It provides predictions for grazing occultations of stars by the Moon and predictions for occultations of stars by asteroids and planets, information on observing equipment and techniques, and reports to the members of observations made.
www.occultations.org Details