- Utah Skies
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.
- The International Astronomical Union (IAU)
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.
- 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.
- The Astronomical League
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.
- The Astronomical Society of South Australia
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.
- 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.
- Night Sky Live
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.