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.

is composed of over two hundred local amateur astronomical societies from all across the United States. Find out about our GREAT national conventions (ALCons)! Member Societies, Regions, Astronomy Day, 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 popular interest in Astronomy.

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

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 such bodies.

European Section (IOTA/ES)

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.

A network of volunteers have cameras focused on the sky to create a 360 degree map of the planets and stars at one time. Data is fed into a computer and filtered for atmospheric interference. Page includes details of the procedure, as well as a discussion forum.

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

Promotes international interdisciplinary programs in solar-terrestrial physics, and organizes and coordinates such programs. Site has a newsletter, meetings and events, member directory, announcements, and links to related groups.

A very comprehensive collection of information useful and interesting to amateur astronomers, especially those located in Utah. Includes events, news, data and reference materials, and a weekly viewing conditions forecast. Has a special section about light pollution.

An international society of amateur and professional astronomers specialising in the observation of double stars and 'deep sky' objects, founded in 1967.