# American Association of Variable Star Observers

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Organization of amateur and professional astronomers

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The **American Association of Variable Star Observers** (**AAVSO**) is an international [nonprofit](/source/Nonprofit_organization) organization. Founded in 1911, the organization focuses on coordinating, analyzing, publishing, and archiving [variable star](/source/Variable_star) observations made largely by [amateur astronomers](/source/Amateur_astronomy).[1] The AAVSO creates records that establish [light curves](/source/Light_curves) depicting the variation in brightness of a [star](/source/Star) over time. The AAVSO makes these records available to professional [astronomers](/source/Astronomers), researchers, and educators.

Professional astronomers do not have the resources to monitor every [variable star](/source/Variable_star). Hence, [astronomy](/source/Astronomy) is one of the few sciences where [amateurs](/source/Citizen_science) can make significant contributions to research.[2] In 2011, the 100th year of the AAVSO's existence, the twenty-millionth variable star observation was received into their database.[3] The AAVSO International Database (AID) has stored over thirty-five million observations as of 2019.[4] The organization receives nearly 1,000,000 observations annually from an estimated amount of 2,000 professional and amateur observers, and is quoted regularly in scientific journals.[5][6][7] The International Variable Star Index (VSX) website, maintained by the AAVSO, is cataloging (as of November 2023) *10,300,863* variable stars.[8]

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 co-authors. In the 1990s, the AAVSO developed the Hands-On Astrophysics curriculum, now known as Variable Star Astronomy[9] (with support from the [National Science Foundation](/source/National_Science_Foundation) [NSF]). In 2009, the AAVSO was awarded a three-year $800,000 grant from the NSF to run Citizen Sky,[10] a pro-am collaboration project examining the 2009-2011 eclipse of the star [epsilon Aurigae](/source/Epsilon_Aurigae).[11]

The AAVSO headquarters was originally located at the residence of its founder [William T. Olcott](/source/William_Tyler_Olcott) in [Norwich, Connecticut](/source/Norwich%2C_Connecticut).

[Minor Planet](/source/Asteroid) [(8900) *AAVSO*](/source/8900_AAVSO) is named after the organization.[12]

## History

After AAVSO's incorporation in 1918, it unofficially moved to [Harvard College Observatory](/source/Harvard_College_Observatory), which later served as the official AAVSO headquarters (1931–1953).[13] Thereafter, it moved around [Cambridge](/source/Cambridge%2C_Massachusetts) before their first building was purchased in 1985: the [Clinton B. Ford](/source/Clinton_B._Ford) Astronomical Data and Research Center.[14] In 2007, the AAVSO purchased and moved into the recently vacated premises of [*Sky & Telescope*](/source/Sky_and_telescope) magazine.[15]

As of September 16, 2022, the Executive Director of the AAVSO is Brian Kloppenborg. Before he assumed this role, Kathy Spirer worked in this capacity for nine months, following the resignation of Styliani ("Stella") Kafka -who was in charge from February 2015 till the ember months of 2021. She succeeded [Arne Henden](/source/Arne_Henden). The previous director of the AAVSO for many decades was [Janet Mattei](/source/Janet_Mattei), who died in March 2004 of [leukemia](/source/Leukemia).[16]

AAVSO members in 1916, meeting at Harvard College Observatory. The two women in the photograph are [Ida E. Woods](/source/Ida_E._Woods) (front row) and [Annie Jump Cannon](/source/Annie_Jump_Cannon) (behind Woods).

## Current and former members

**Recorders and Directors**

- [William T. Olcott](/source/William_Tyler_Olcott) (1911–1918, Founder)

- [Leon Campbell](/source/Leon_Campbell_(astronomer)) (1915–1949)

- [Margaret Mayall](/source/Margaret_Mayall) (1949–1973)

- [Janet A. Mattei](/source/Janet_Aky%C3%BCz_Mattei) (AAVSO Director 1973–2003)

- [Elizabeth O. Waagen](https://en.wikipedia.org/w/index.php?title=Elizabeth_O._Waagen&action=edit&redlink=1) (2003–2005)

- [Arne Henden](/source/Arne_Henden) (2005–2015)

- [Styliani ("Stella") Kafka](https://en.wikipedia.org/w/index.php?title=Styliani_(%22Stella%22)_Kafka&action=edit&redlink=1) (2015–2021)

- [Kathy Spirer](https://en.wikipedia.org/w/index.php?title=Kathy_Spirer&action=edit&redlink=1) (2022)

- [Brian Kloppenborg](https://en.wikipedia.org/w/index.php?title=Brian_Kloppenborg&action=edit&redlink=1) (2022–)

**Presidents [17]**

- [David B. Pickering](https://en.wikipedia.org/w/index.php?title=David_B._Pickering&action=edit&redlink=1) (1917–1918)

- [Harold C. Bancroft Jr.](https://en.wikipedia.org/w/index.php?title=Harold_C._Bancroft_Jr.&action=edit&redlink=1) (1918–1919)

- [Leon Campbell](/source/Leon_Campbell_(astronomer)) (1919–1922)

- [Anne S. Young](/source/Anne_S._Young) (1922–1924)

- [J. Ernest G. Yalden](https://en.wikipedia.org/w/index.php?title=J._Ernest_G._Yalden&action=edit&redlink=1) (1924–1926)

- [Charles C. Godfrey](https://en.wikipedia.org/w/index.php?title=Charles_C._Godfrey&action=edit&redlink=1) (1926–1927)

- David B. Pickering (1927–1929)

- [Alice H. Farnsworth](/source/Alice_H._Farnsworth) (1929–1931)

- [Harriet W. Bigelow](/source/Harriet_W._Bigelow) (1931–1933)

- [Ernest W. Brown](/source/Ernest_W._Brown) (1933–1935)

- [Harlow Shapley](/source/Harlow_Shapley) (1935–1937)

- [Charles W. Elmer](/source/Charles_W._Elmer) (1937–1939)

- [Helen S. Hogg](/source/Helen_S._Hogg) (1939–1941)

- [Dirk Brouwer](/source/Dirk_Brouwer) (1941–1943)

- [Roy A. Seely](https://en.wikipedia.org/w/index.php?title=Roy_A._Seely&action=edit&redlink=1) (1943–1945)

- [Charles H. Smiley](/source/Charles_H._Smiley) (1945–1947)

- [Marjorie Williams](/source/Marjorie_Williams) (1947–1948)

- [David W. Rosebrugh](https://en.wikipedia.org/w/index.php?title=David_W._Rosebrugh&action=edit&redlink=1) (1948–1949)

- [Neal J. Heines](https://en.wikipedia.org/w/index.php?title=Neal_J._Heines&action=edit&redlink=1) (1949–1951)

- [Martha Stahr Carpenter](/source/Martha_Stahr_Carpenter) (1951–1954)

- [Cyrus F. Fernald](https://en.wikipedia.org/w/index.php?title=Cyrus_F._Fernald&action=edit&redlink=1) (1954–1956)

- [Richard W. Hamilton](https://en.wikipedia.org/w/index.php?title=Richard_W._Hamilton&action=edit&redlink=1) (1956–1958)

- [Ralph N. Buckstaff](https://en.wikipedia.org/w/index.php?title=Ralph_N._Buckstaff&action=edit&redlink=1) (1958–1960)

- [E. Dorrit Hoffleit](/source/E._Dorrit_Hoffleit) (1961–1963)

- [George Diedrich](https://en.wikipedia.org/w/index.php?title=George_Diedrich&action=edit&redlink=1) (1963–1965)

- [Edward G. Oravec](https://en.wikipedia.org/w/index.php?title=Edward_G._Oravec&action=edit&redlink=1) (1965–1967)

- [Charles M. Good](https://en.wikipedia.org/w/index.php?title=Charles_M._Good&action=edit&redlink=1) (1971–1973)

- [Casper H. Hossfield](https://en.wikipedia.org/w/index.php?title=Casper_H._Hossfield&action=edit&redlink=1) (1969–1971)

- [Frank J. DeKinder](https://en.wikipedia.org/w/index.php?title=Frank_J._DeKinder&action=edit&redlink=1) (1967–1969)

- [Charles E. Scovil](https://en.wikipedia.org/w/index.php?title=Charles_E._Scovil&action=edit&redlink=1) (1973–1975)

- [George L. Fortier](https://en.wikipedia.org/w/index.php?title=George_L._Fortier&action=edit&redlink=1) (1975–1977)

- [Marvin E. Baldwin](https://en.wikipedia.org/w/index.php?title=Marvin_E._Baldwin&action=edit&redlink=1) (1977–1979)

- [Carl A. Anderson](/source/Carl_A._Anderson) (1979–1981)

- [Arthur J. Stokes](https://en.wikipedia.org/w/index.php?title=Arthur_J._Stokes&action=edit&redlink=1) (1981–1983)

- [Ernst H. Mayer](https://en.wikipedia.org/w/index.php?title=Ernst_H._Mayer&action=edit&redlink=1) (1983–1985)

- [Thomas R. Williams](/source/Thomas_R._Williams) (1985–1987)

- [Keith H. Danskin](https://en.wikipedia.org/w/index.php?title=Keith_H._Danskin&action=edit&redlink=1) (1987–1989)

- [John R. Percy](https://en.wikipedia.org/w/index.php?title=John_R._Percy&action=edit&redlink=1) (1989–1991)

- [Martha Locke Hazen](/source/Martha_Locke_Hazen) (1991–1992)

- Thomas R. Williams (1992–1993)

- [Wayne M. Lowder](https://en.wikipedia.org/w/index.php?title=Wayne_M._Lowder&action=edit&redlink=1) (1993–1995)

- [Albert V. Holm](https://en.wikipedia.org/w/index.php?title=Albert_V._Holm&action=edit&redlink=1) (1995–1997)

- Gary Walker (1997–1999)

- [Lee Anne Willson](/source/Lee_Anne_Willson) (1999–2001)

- [Daniel H. Kaiser](https://en.wikipedia.org/w/index.php?title=Daniel_H._Kaiser&action=edit&redlink=1) (2001–2003)

- [William G. Dillon](https://en.wikipedia.org/w/index.php?title=William_G._Dillon&action=edit&redlink=1) (2003–2005)

- David B. Williams (2005–2007)

- [Paula Szkody](/source/Paula_Szkody) (2007–2009)

- [Jaime R. Garcia](https://en.wikipedia.org/w/index.php?title=Jaime_R._Garcia&action=edit&redlink=1) (2009–2011)

- Mario E. Motta (2011–2013)

- Jennifer (Jeno) Sokoloski (2013–2015)

- Kristine M. Larsen (2015–2018)

- Gordon Myers (2018–2021)

- David Cowall (2021–2024)

**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](/source/Leah_B._Allen) Charter Member [18]

- [Joseph Ashbrook](/source/Joseph_Ashbrook)

- [Rosina Dafter](/source/Rosina_Dafter)

- [Radha Gobinda Chandra](/source/Radha_Gobinda_Chandra)[19]

- [Robert Evans](/source/Robert_Evans_(astronomer)) (AAVSO Supernova Search Committee Chairperson 1985–2005)

- [Clinton B. Ford](/source/Clinton_B._Ford)

- [Russell Merle Genet](/source/Russell_Merle_Genet)

- [Pamela L. Gay](/source/Pamela_L._Gay)

- [Edward A. Halbach](/source/Edward_A._Halbach)

- [Phoebe Waterman Haas](/source/Phoebe_Waterman_Haas)

- [Carolyn Hurless](/source/Carolyn_Hurless)

- [Richard Huziak](/source/Richard_Huziak)

- [Albert F. A. L. Jones](/source/Albert_F._A._L._Jones)

- [Giovanni B. Lacchini](/source/Giovanni_Battista_Lacchini)

- [Helen Lines](/source/Helen_Lines)

- [Richard D. Lines](/source/Richard_D._Lines)

- [Ben Mayer](/source/Ben_Mayer)

- [Ruth J. Northcott](/source/Ruth_J._Northcott)

- [Arto Oksanen](/source/Arto_Oksanen)

- [M. Daniel Overbeek](/source/Michiel_Daniel_Overbeek)

- [Leslie Peltier](/source/Leslie_Peltier)

- [Lois Tripp Slocum](/source/Lois_Tripp_Slocum)

- [Peter Francis Williams](/source/Peter_Francis_Williams)

- [Ida E. Woods](/source/Ida_E._Woods)

## Publications

- *AAVSO Alert Notice*.

- [*Journal of the American Association of Variable Star Observers* (JAAVSO)](https://www.aavso.org/apps/jaavso/).

- *AAVSO Circular* was published from 1970 until 2000 and edited by [John E. Bortle](/source/John_E._Bortle).[20]

## See also

- [List of astronomical societies](/source/List_of_astronomical_societies)

## References

1. **[^](#cite_ref-1)** 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](/source/Journal_of_the_American_Association_of_Variable_Star_Observers)*. **27** (2): 154–170. [Bibcode](/source/Bibcode_(identifier)):[1999JAVSO..27..154S](https://ui.adsabs.harvard.edu/abs/1999JAVSO..27..154S).

1. **[^](#cite_ref-2)** Ferris, T. (2003). *Seeing in the Dark: How Amateur Astronomers Are Discovering the Wonders of the Universe*. [Simon & Schuster](/source/Simon_%26_Schuster). p. 54. [ISBN](/source/ISBN_(identifier)) [0-684-86580-7](https://en.wikipedia.org/wiki/Special:BookSources/0-684-86580-7).

1. **[^](#cite_ref-3)** Simonsen, M. (February 23, 2011). ["20 Million Observations by Amateur Astronomers"](http://www.universetoday.com/83479/20-million-observations-by-amateur-astronomers/). *[Universe Today](/source/Universe_Today)*. [Archived](https://web.archive.org/web/20110301023401/http://www.universetoday.com/83479/20-million-observations-by-amateur-astronomers/) from the original on 2011-03-01. Retrieved 2011-05-16.

1. **[^](#cite_ref-4)** ["35 million points and counting! | aavso.org"](https://www.aavso.org/35-million-points-and-counting). *www.aavso.org*. [Archived](https://web.archive.org/web/20190529150505/https://www.aavso.org/35-million-points-and-counting) from the original on 2019-05-29. Retrieved 2018-04-11.

1. **[^](#cite_ref-PERCY_5-0)** Percy, J. R.; Desjardins, A.; Yu, L.; Landis, H. J. (2002). ["Small Amplitude Red Variables in the AAVSO Photoelectric Program: Light Curves and Periods"](https://doi.org/10.1086%2F133703). *[Publications of the Astronomical Society of the Pacific](/source/Publications_of_the_Astronomical_Society_of_the_Pacific)*. **108**: 139. [Bibcode](/source/Bibcode_(identifier)):[1996PASP..108..139P](https://ui.adsabs.harvard.edu/abs/1996PASP..108..139P). [doi](/source/Doi_(identifier)):[10.1086/133703](https://doi.org/10.1086%2F133703).

1. **[^](#cite_ref-CANNIZZO_6-0)** Cannizzo, J. K. (2002). ["The Accretion Disk Limit Cycle Model: Toward an Understanding of the Long-Term Behavior of SS Cygni"](https://zenodo.org/record/1235674). *[The Astrophysical Journal](/source/The_Astrophysical_Journal)*. **419**: 318. [Bibcode](/source/Bibcode_(identifier)):[1993ApJ...419..318C](https://ui.adsabs.harvard.edu/abs/1993ApJ...419..318C). [doi](/source/Doi_(identifier)):[10.1086/173486](https://doi.org/10.1086%2F173486). [Archived](https://web.archive.org/web/20220129214608/https://zenodo.org/record/1235674) from the original on 2022-01-29. Retrieved 2019-06-30.

1. **[^](#cite_ref-KISS_7-0)** Kiss, L. L.; Szatmáry, K.; Cadmus, R. R. Jr.; Mattei, J. A. (1999). "Multiperiodicity in semiregular variables. I. General properties". *[Astronomy and Astrophysics](/source/Astronomy_and_Astrophysics)*. **346**: 542–555. [arXiv](/source/ArXiv_(identifier)):[astro-ph/9904128](https://arxiv.org/abs/astro-ph/9904128). [Bibcode](/source/Bibcode_(identifier)):[1999A&A...346..542K](https://ui.adsabs.harvard.edu/abs/1999A&A...346..542K).

1. **[^](#cite_ref-8)** ["The International Variable Star Index (VSX)"](https://www.aavso.org/vsx/). *www.aavso.org*. Retrieved 2023-11-01.

1. **[^](#cite_ref-9)** ["Variable Star Astronomy"](http://www.aavso.org/education/vsa/). [Archived](https://web.archive.org/web/20210421221359/https://www.aavso.org/education/vsa) from the original on 2021-04-21. Retrieved 2010-02-19.

1. **[^](#cite_ref-10)** ["Citizen Sky"](https://web.archive.org/web/20161201190005/http://www.citizensky.org/). Archived from [the original](http://www.citizensky.org/) on 2016-12-01. Retrieved 2019-05-17.

1. **[^](#cite_ref-11)** ["NSF.gov"](https://www.nsf.gov/awardsearch/showAward.do?AwardNumber=0840188&WT.z_pims_id=5361). [Archived](https://web.archive.org/web/20220129214611/https://www.nsf.gov/awardsearch/showAward?AWD_ID=0840188) from the original on 2022-01-29. Retrieved 2018-04-06.

1. **[^](#cite_ref-12)** ["(8900) AAVSO = 1995 UD2"](http://www.minorplanetcenter.net/iau/ECS/MPCArchive/2003/MPC_20030501.pdf) (PDF). *[Minor Planet Circular](/source/Minor_Planet_Circular)*. [Minor Planet Center](/source/Minor_Planet_Center). 1 May 2003. [Archived](https://web.archive.org/web/20120612052429/http://www.minorplanetcenter.net/iau/ECS/MPCArchive/2003/MPC_20030501.pdf) (PDF) from the original on 2012-06-12. Retrieved 2012-07-14.

1. **[^](#cite_ref-13)** Williams, T. R.; Saladyga, M. (2011). *Advancing Variable Star Astronomy - The Centennial History of the American Association of Variable Star Observers*. [Cambridge University Press](/source/Cambridge_University_Press). [ISBN](/source/ISBN_(identifier)) [978-0-521-51912-0](https://en.wikipedia.org/wiki/Special:BookSources/978-0-521-51912-0).

1. **[^](#cite_ref-14)** [Clinton B. Ford Astronomical Data and Research Center](http://www.aavso.org/aavso/about/hq.shtml) [Archived](https://web.archive.org/web/20061231195004/http://www.aavso.org/aavso/about/hq.shtml) 2006-12-31 at the [Wayback Machine](/source/Wayback_Machine)

1. **[^](#cite_ref-15)** ["AAVSO.org"](https://web.archive.org/web/20200918063037/http://www.aavso.org/news/49baypress.shtml). Archived from [the original](http://www.aavso.org/news/49baypress.shtml) on 2020-09-18. Retrieved 2007-01-18.

1. **[^](#cite_ref-16)** Williams, T. R.; Willson, L. A. (2004). "Obituary: Janet Akyüz Mattei, 1943-2004". *[Bulletin of the American Astronomical Society](/source/Bulletin_of_the_American_Astronomical_Society)*. **36** (5): 1681–1682. [Bibcode](/source/Bibcode_(identifier)):[2004BAAS...36.1681W](https://ui.adsabs.harvard.edu/abs/2004BAAS...36.1681W).

1. **[^](#cite_ref-17)** ["Officers of the AAVSO since 1911"](https://www.aavso.org/officers-aavso-1911-2014). [Archived](https://web.archive.org/web/20210709190323/https://www.aavso.org/officers-aavso-1911-2014) from the original on 2021-07-09. Retrieved 2021-07-09.

1. **[^](#cite_ref-18)** Dorrit Hoffleit "The Maria Mitchell Observatory: For Astronomical Research and Public Enlightenment" Journal of the American Association of Variable Star Observers Volume 30, 2001, p70, [AAVSO.org](http://www.aavso.org/publications/ejaavso/v30n1/62.pdf) [Archived](https://web.archive.org/web/20090109201922/http://www.aavso.org/publications/ejaavso/v30n1/62.pdf) 2009-01-09 at the [Wayback Machine](/source/Wayback_Machine) where her photograph from 1930 appears.

1. **[^](#cite_ref-19)** ["AAVSO: Part Four: The AAVSO and International Cooperation"](http://www.aavso.org/aavso/history/webhist4.shtml). [Archived](https://web.archive.org/web/20090608033315/http://www.aavso.org/aavso/history/webhist4.shtml) from the original on 2009-06-08. Retrieved 2009-07-13.

1. **[^](#cite_ref-20)** ["John E. Bortle - 2013 Leslie Peltier Award"](https://web.archive.org/web/20150620002810/https://www.astroleague.org/content/john-e-bortle-2013-leslie-peltier-award-0). Archived from [the original](http://www.astroleague.org/content/john-e-bortle-2013-leslie-peltier-award-0) on 20 June 2015. Retrieved 26 September 2014.

## External links

- [AAVSO website](http://www.aavso.org/)

- [The International Variable Star Index](https://www.aavso.org/vsx/index.php) (VSX)

- [History of the AAVSO](http://www.aavso.org/history-aavso)

- [Amateur Astronomy Reaches New Heights](https://web.archive.org/web/20090814151017/http://www.space.com/scienceastronomy/astronomy/stargazing_gamma_ray_000629.html) Space.com, June 28, 2000

- [A New Foundation for the AAVSO](https://web.archive.org/web/20120309153022/http://www.skyandtelescope.com/news/4989341.html) article in the January 2007 issue of *[Sky & Telescope](/source/Sky_%26_Telescope)* magazine

- [Red Hot News… Possible Nova in Sagittarius!](http://www.universetoday.com/2009/08/07/red-hot-news-possible-nova-in-sagittarius/) *[Universe Today](/source/Universe_Today)*, August 9, 2009

- [100 Years of Citizen Science](http://www.aavso.org/100-years-citizen-science) (1 December 2010)

[Portals](https://en.wikipedia.org/wiki/Wikipedia:Contents/Portals):
- [United States](https://en.wikipedia.org/wiki/Portal:United_States)
- [Astronomy](https://en.wikipedia.org/wiki/Portal:Astronomy)
- [Stars](https://en.wikipedia.org/wiki/Portal:Stars)
- [Outer space](https://en.wikipedia.org/wiki/Portal:Outer_space)

Authority control databases International ISNI VIAF GND National United States France BnF data Czech Republic Israel Croatia Academics CiNii Other IdRef Yale LUX

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Adapted from the Wikipedia article [American Association of Variable Star Observers](https://en.wikipedia.org/wiki/American_Association_of_Variable_Star_Observers) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/American_Association_of_Variable_Star_Observers?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.