- American Astronomical Society
This is one of the main associations for professional astronomers based anywhere the world. There are over 6,400 individual members. The web site provides information about their journals, committees, divisions, meetings, career services and more.
- Astronomical Society of the Pacific (ASP)
Founded in 1889, the ASP is an international nonprofit scientific and educational organization that works to increase the understanding and appreciation of astronomy. They have become the largest general astronomy society in the world, with members from over 70 nations. The education section is particularly impressive -- http://www.astrosociety.org/education.html, with some introductory overviews and bibliographies that librarians might be interested in. Some of them are: "Astronomy Education in the U.S.: An Overview," "Astronomy Education Bibliography," "Women in Astronomy: An Introductory Bibliography," and their "Astronomical Pseudo-Science: A Skeptic's Bibliography."
- Association of Universities for Research in Astronomy (AURA)
AURA is a consortium of universities, and educational and other non-profit institutions, that operates world-class astronomical observatories. Its members include 39 U.S. Institutions and 7 international affiliates.
- International Astronomical Union (IAU)
Founded in 1919. Promotes the science of astronomy in all its aspects through international cooperation. Individual members number over 8,300 professional astronomers from 66 countries. Serves as the internationally recognized authority for assigning designations and names to celestial bodies and any surface features. In other words, one can not purchase a name for a star and get it recognized in the astronomical community -- http://www.iau.org/IAU/FAQ/starnames.html.
- The Royal Astronomical Society (UK)
Founded in 1820. Promotes the study of astronomy, solar-system science, geophysics and closely related branches of science.
- European Astronomical Society (EAS)
Founded in 1990. Promoted and advances astronomy in Europe.
- Astronomical Society of Australia
Formed in 1966. The web site contains links to information concerning their membership, meetings, publications, education activities, etc. If one is interested in learning more about astronomical activities in Australia, they have a freely available newsletter -- http://www.atnf.csiro.au/asa_www/newsletter.html