American Association of Variable Star Observers
Since its founding in 1911, the American Association of Variable Star Observers (AAVSO) has coordinated, collected, evaluated, analyzed, published, and archived variable star observations made largely by amateur astronomers and makes the records available to professional astronomers, researchers, and educators. These records establish light curves depicting the variation in brightness of a star over time.
Since professional astronomers do not have the time or the resources to monitor every variable star, astronomy is one of the few sciences where amateurs can make genuine contributions to scientific research. During 2011, the 100th year of the AAVSO's existence, the 20-millionth variable star observation was received into the database.  The AAVSO International Database currently stores over 35 million observations.  The organization receives nearly 1,000,000 observations annually from around 2,000 professional and amateur observers and is quoted regularly in scientific journals.
The AAVSO is also very active in education and public outreach. They routinely hold training workshops for citizen science and publish papers with amateurs as coauthors. In the 1990s, the AAVSO developed the Hands-On Astrophysics curriculum, now known as Variable Star Astronomy (with support from the National Science Foundation (NSF)). In 2009, the AAVSO was awarded a three-year $800,000 grant from the NSF to run Citizen Sky, a pro-am collaboration project examining the 2009-2011 eclipse of the star epsilon Aurigae.
The current director of the AAVSO is Stella Kafka, who took over from Arne Henden in February 2015. The previous director of the AAVSO for many decades was Janet Mattei, who died in March 2004 of leukemia.
The AAVSO headquarters were originally located at the residence of its founder William T. Olcott in Norwich, Connecticut. After AAVSO's incorporation in 1918 it de facto moved to Harvard College Observatory, which later officially provided an office as the AAVSO headquarters (1931–1953). After then it moved around Cambridge before purchasing their first building in 1985 - The Clinton B. Ford Astronomical Data and Research Center. In 2007, the AAVSO purchased and moved into the recently vacated premises of Sky & Telescope magazine.
Current and former members
- Recorders and Directors
- David B. Pickering (1917–1918)
- Harold C. Bancroft, Jr. (1918–1919)
- Leon Campbell (1919–1922)
- Anne S. Young (1922–1924)
- J. Ernest G. Yalden (1924–1926)
- Charles C. Godfrey (1926–1927)
- David B. Pickering (1927–1929)
- Alice H. Farnsworth (1929–1931)
- Harriet W. Bigelow (1931–1933)
- Ernest W. Brown (1933–1935)
- Harlow Shapley (1935–1937)
- Charles W. Elmer (1937–1939)
- Helen S. Hogg (1939–1941)
- Dirk Brouwer (1941–1943)
- Roy A. Seely (1943–1945)
- Charles H. Smiley (1945–1947)
- Marjorie Williams (1947–1948)
- David W. Rosebrugh (1948–1949)
- Neal J. Heines (1949–1951)
- Martha Stahr Carpenter (1951–1954)
- Cyrus F. Fernald (1954–1956)
- Richard W. Hamilton (1956–1958)
- Ralph N. Buckstaff (1958–1960)
- E. Dorrit Hoffleit (1961–1963)
- George Diedrich (1963–1965)
- Edward G. Oravec (1965–1967)
- Charles M. Good (1971–1973)
- Casper H. Hossfield (1969–1971)
- Frank J. DeKinder (1967–1969)
- Charles E. Scovil (1973–1975)
- George L. Fortier (1975–1977)
- Marvin E. Baldwin (1977–1979)
- Carl A. Anderson (1979–1981)
- Arthur J. Stokes (1981–1983)
- Ernst H. Mayer (1983–1985)
- Thomas R. Williams (1985–1987)
- Keith H. Danskin (1987–1989)
- John R. Percy (1989–1991)
- Martha L. Hazen (1991–1992)
- Thomas R. Williams (1992–1993)
- Wayne M. Lowder (1993–1995)
- Albert V. Holm (1995–1997)
- Gary Walker (1997–1999)
- Lee Anne Willson (1999–2001)
- Daniel H. Kaiser (2001–2003)
- William G. Dillon (2003–2005)
- David B. Williams (2005–2007)
- Paula Szkody (2007–2009)
- Jaime R. Garcia (2009–2011)
- Other members
The AAVSO currently has over 2,000 members and observers, with approximately half of them from outside the United States. This list only consists of those with Wikipedia pages.
- Leah B. Allen Charter Member 
- Joseph Ashbrook
- Rosina Dafter
- Radha Gobinda Chandra
- Robert Evans (AAVSO Supernova Search Committee Chairperson 1985–2005)
- Clinton B. Ford
- Russell Merle Genet
- Pamela L. Gay
- Edward A. Halbach
- Phoebe Waterman Haas
- Carolyn Hurless
- Richard Huziak
- Albert F. A. L. Jones
- Michael Koppelman
- Giovanni B. Lacchini
- Helen Lines
- Richard D. Lines
- Ben Mayer
- Arto Oksanen
- M. Daniel Overbeek
- Leslie Peltier
- Peter Francis Williams
- AAVSO Alert Notice.
- Journal of the American Association of Variable Star Observers (JAAVSO).
- AAVSO Circular was published from 1970 until 2000 and edited by John E. Bortle.
- Saladyga, M. (1999). "The "Pre-Embryonic" State of the AAVSO: Amateur Observers of Variable Stars in the United States From 1875 to 1911". Journal of the American Association of Variable Star Observers. 27 (2): 154–170. Bibcode:1999JAVSO..27..154S.
- Ferris, T. (2003). Seeing in the Dark: How Amateur Astronomers Are Discovering the Wonders of the Universe. Simon & Schuster. p. 54. ISBN 0-684-86580-7.
- Simonsen, M. (February 23, 2011). "20 Million Observations by Amateur Astronomers". Universe Today. Retrieved 2011-05-16.
- "35 million points and counting! | aavso.org". www.aavso.org. Retrieved 2018-04-11.
- Percy, J. R.; Desjardins, A.; Yu, L.; Landis, H. J. (2002). "Small Amplitude Red Variables in the AAVSO Photoelectric Program: Light Curves and Periods". Publications of the Astronomical Society of the Pacific. 108: 139. Bibcode:1996PASP..108..139P. doi:10.1086/133703.
- Cannizzo, J. K. (2002). "The Accretion Disk Limit Cycle Model: Toward an Understanding of the Long-Term Behavior of SS Cygni". The Astrophysical Journal. 419: 318. Bibcode:1993ApJ...419..318C. doi:10.1086/173486.
- Kiss, L. L.; Szatmáry, K.; Cadmus, R. R. Jr.; Mattei, J. A. (1999). "Multiperiodicity in semiregular variables. I. General properties". Astronomy and Astrophysics. 346: 542–555. arXiv: . Bibcode:1999A&A...346..542K.
- Variable Star Astronomy
- Citizen Sky
- Williams, T. R.; Willson, L. A. (2004). "Obituary: Janet Akyüz Mattei, 1943-2004". Bulletin of the American Astronomical Society. 36 (5): 1681–1682. Bibcode:2004BAAS...36.1681W.
- Williams, T. R.; Saladyga, M. (2011). Advancing Variable Star Astronomy - The Centennial History of the American Association of Variable Star Observers. Cambridge University Press. ISBN 978-0-521-51912-0.
- Clinton B. Ford Astronomical Data and Research Center Archived 2006-12-31 at the Wayback Machine.
- "(8900) AAVSO = 1995 UD2" (PDF). Minor Planet Circular. Minor Planet Center. 1 May 2003. Retrieved 2012-07-14.
- Dorrit Hoffleit "The Maria Mitchell Observatory: For Astronomical Research and Public Enlightenment" JAAVSO Volume 30, 2001, p70, AAVSO.org Archived 2009-01-09 at the Wayback Machine. where her photograph from 1930 appears.
- AAVSO: Part Four: The AAVSO and International Cooperation
- "John E. Bortle - 2013 Leslie Peltier Award". Archived from the original on 20 June 2015. Retrieved 26 September 2014.
- AAVSO website
- History of the AAVSO
- Amateur Astronomy Reaches New Heights Space.com, June 28, 2000
- A New Foundation for the AAVSO article in the January 2007 issue of Sky & Telescope magazine
- Red Hot News… Possible Nova in Sagittarius! Universe Today, August 9, 2009
- 100 Years of Citizen Science (1 December 2010)