Professional and Amateur collection, research, and analysis of variable star observations.

Established 1899, AAS is the major professional organization in North America for astronomers, other scientists and individuals interested in astronomy.

A medium for advancing and conducting work by both professional and amateur astronomers who share an interest in Solar System observations. Includes publications, programs, and image archive.

Composed of over two hundred local amateur astronomical societies from across the United States. Information on national conventions (ALCons), member societies, regions, Astronomy Day, and awards.

Founded in 1892, is the oldest society of its kind in Australia. Its objectives are to promote the Science of Astronomy and all its branches by holding regular meetings and viewing nights, circulating current astronomical information, and encouraging popu

Disseminates astronomical information. The ASP has become the largest general astronomy society in the world, with members from over 70 nations.

An association founded under the Swiss Civil Code in 1990. Its purpose is to contribute to and promote the advancement of astronomy in Europe.

Founded in 1919, has a mission to promote and safeguard the science of astronomy through international cooperation. The organization is also the internationally recognized authority for assigning designations to celestial bodies and surface features on su

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 equipm

A project consisting of predictions and data for the moon, asteroids, and planets.

A nonprofit organization that promotes exploration of the solar system and the search for extraterrestrial intelligence.

Key activities include research and observing planets, stars, celestial phenomena and the abatement of light pollution.

An international society of amateurs and professionals specialising in the observation of double stars and deep sky objects, founded in 1967.