{{Short description|Organization of amateur and professional astronomers}}{{Advertisment|date=April 2025}}
The '''American Association of Variable Star Observers''' ('''AAVSO''') is an international [[Nonprofit organization|nonprofit]] organization. Founded in 1911, the organization focuses on coordinating, analyzing, publishing, and archiving [[variable star]] observations made largely by [[amateur astronomy|amateur astronomers]].<ref> {{cite journal |last=Saladyga |first=M. |date=1999 |title=The "Pre-Embryonic" State of the AAVSO: Amateur Observers of Variable Stars in the United States From 1875 to 1911 |journal=[[Journal of the American Association of Variable Star Observers]] |volume=27 |issue=2 |pages=154–170 |bibcode=1999JAVSO..27..154S}}</ref> The AAVSO creates records that establish [[light curves]] depicting the variation in brightness of a [[star]] over time. The AAVSO makes these records available to professional [[astronomers]], researchers, and educators.
Professional astronomers do not have the resources to monitor every [[variable star]]. Hence, [[astronomy]] is one of the few sciences where [[citizen science|amateurs]] can make significant contributions to research.<ref> {{cite book |last=Ferris |first=T. |date=2003 |title=Seeing in the Dark: How Amateur Astronomers Are Discovering the Wonders of the Universe |page=54 |publisher=[[Simon & Schuster]] |isbn=0-684-86580-7 }}</ref> In 2011, the 100th year of the AAVSO's existence, the twenty-millionth variable star observation was received into their database.<ref>{{cite web |last=Simonsen |first=M. |date=February 23, 2011 |title=20 Million Observations by Amateur Astronomers |url=http://www.universetoday.com/83479/20-million-observations-by-amateur-astronomers/ |work=[[Universe Today]] |access-date=2011-05-16 |archive-date=2011-03-01 |archive-url=https://web.archive.org/web/20110301023401/http://www.universetoday.com/83479/20-million-observations-by-amateur-astronomers/ |url-status=live }}</ref> The AAVSO International Database (AID) has stored over thirty-five million observations as of 2019.<ref>{{Cite web|url=https://www.aavso.org/35-million-points-and-counting|title=35 million points and counting! {{!}} aavso.org|website=www.aavso.org|language=en|access-date=2018-04-11|archive-date=2019-05-29|archive-url=https://web.archive.org/web/20190529150505/https://www.aavso.org/35-million-points-and-counting|url-status=live}}</ref> 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.<ref name="PERCY"> {{cite journal |last1=Percy |first1=J. R. |last2=Desjardins |first2=A. |last3=Yu |first3=L. |last4=Landis |first4=H. J. |date=2002 |title=Small Amplitude Red Variables in the AAVSO Photoelectric Program: Light Curves and Periods |journal=[[Publications of the Astronomical Society of the Pacific]] |volume=108 |pages=139 |bibcode=1996PASP..108..139P |doi=10.1086/133703 |doi-access=free }}</ref><ref name="CANNIZZO">{{cite journal |last=Cannizzo |first=J. K. |date=2002 |title=The Accretion Disk Limit Cycle Model: Toward an Understanding of the Long-Term Behavior of SS Cygni |journal=[[The Astrophysical Journal]] |volume=419 |pages=318 |bibcode=1993ApJ...419..318C |doi=10.1086/173486 |url=https://zenodo.org/record/1235674 |access-date=2019-06-30 |archive-date=2022-01-29 |archive-url=https://web.archive.org/web/20220129214608/https://zenodo.org/record/1235674 |url-status=live }}</ref><ref name="KISS"> {{cite journal |last1=Kiss |first1=L. L. |last2=Szatmáry |first2=K. |last3=Cadmus |first3=R. R. Jr. |last4=Mattei |first4=J. A. |date=1999 |title=Multiperiodicity in semiregular variables. I. General properties |journal=[[Astronomy and Astrophysics]] |volume=346 |pages=542–555 |arxiv=astro-ph/9904128 |bibcode=1999A&A...346..542K }}</ref> The International Variable Star Index (VSX) website, maintained by the AAVSO, is cataloging (as of November 2023) ''10,300,863'' variable stars.<ref>{{Cite web |title=The International Variable Star Index (VSX) |url=https://www.aavso.org/vsx/ |access-date=2023-11-01 |website=www.aavso.org}}</ref>
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<ref>{{Cite web |url=http://www.aavso.org/education/vsa/ |title=Variable Star Astronomy |access-date=2010-02-19 |archive-date=2021-04-21 |archive-url=https://web.archive.org/web/20210421221359/https://www.aavso.org/education/vsa |url-status=live }}</ref> (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,<ref>{{Cite web |url=http://www.citizensky.org/ |title=Citizen Sky |access-date=2019-05-17 |archive-url=https://web.archive.org/web/20161201190005/http://www.citizensky.org/ |archive-date=2016-12-01 |url-status=dead }}</ref> a pro-am collaboration project examining the 2009-2011 eclipse of the star [[epsilon Aurigae]].<ref>{{Cite web |url=https://www.nsf.gov/awardsearch/showAward.do?AwardNumber=0840188&WT.z_pims_id=5361 |title=NSF.gov |access-date=2018-04-06 |archive-date=2022-01-29 |archive-url=https://web.archive.org/web/20220129214611/https://www.nsf.gov/awardsearch/showAward?AWD_ID=0840188 |url-status=live }}</ref>
The AAVSO headquarters was originally located at the residence of its founder [[William Tyler Olcott|William T. Olcott]] in [[Norwich, Connecticut]].
[[asteroid|Minor Planet]] [[8900 AAVSO|(8900) ''AAVSO'']] is named after the organization.<ref>{{cite web |date=1 May 2003 |title=(8900) AAVSO = 1995 UD<sub>2</sub> |url=http://www.minorplanetcenter.net/iau/ECS/MPCArchive/2003/MPC_20030501.pdf |url-status=live |archive-url=https://web.archive.org/web/20120612052429/http://www.minorplanetcenter.net/iau/ECS/MPCArchive/2003/MPC_20030501.pdf |archive-date=2012-06-12 |access-date=2012-07-14 |work=[[Minor Planet Circular]] |publisher=[[Minor Planet Center]]}}</ref>
== History == After AAVSO's incorporation in 1918, it unofficially moved to [[Harvard College Observatory]], which later served as the official AAVSO headquarters (1931–1953).<ref> {{cite book |last1=Williams |first1=T. R. |title=Advancing Variable Star Astronomy - The Centennial History of the American Association of Variable Star Observers |last2=Saladyga |first2=M. |date=2011 |publisher=[[Cambridge University Press]] |isbn=978-0-521-51912-0}}</ref> Thereafter, it moved around [[Cambridge, Massachusetts|Cambridge]] before their first building was purchased in 1985: the [[Clinton B. Ford]] Astronomical Data and Research Center.<ref>[http://www.aavso.org/aavso/about/hq.shtml Clinton B. Ford Astronomical Data and Research Center] {{webarchive|url=https://web.archive.org/web/20061231195004/http://www.aavso.org/aavso/about/hq.shtml|date=2006-12-31}}</ref> In 2007, the AAVSO purchased and moved into the recently vacated premises of [[Sky and telescope|''Sky & Telescope'']] magazine.<ref>{{Cite web |title=AAVSO.org |url=http://www.aavso.org/news/49baypress.shtml |url-status=dead |archive-url=https://web.archive.org/web/20200918063037/http://www.aavso.org/news/49baypress.shtml |archive-date=2020-09-18 |access-date=2007-01-18}}</ref>
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]]. The previous director of the AAVSO for many decades was [[Janet Mattei]], who died in March 2004 of [[leukemia]].<ref> {{cite journal |last1=Williams |first1=T. R. |last2=Willson |first2=L. A. |date=2004 |title=Obituary: Janet Akyüz Mattei, 1943-2004 |journal=[[Bulletin of the American Astronomical Society]] |volume=36 |issue=5 |pages=1681–1682 |bibcode=2004BAAS...36.1681W }}</ref> [[File:AAVSO1916.png|alt=Twenty scientists, mostly men, standing for a group photograph in 1916.|thumb|AAVSO members in 1916, meeting at Harvard College Observatory. The two women in the photograph are [[Ida E. Woods]] (front row) and [[Annie Jump Cannon]] (behind Woods).]] ==Current and former members== ;Recorders and Directors {{columns-list|colwidth=20em| *[[William Tyler Olcott|William T. Olcott]] (1911–1918, Founder) *[[Leon Campbell (astronomer)|Leon Campbell]] (1915–1949) *[[Margaret Mayall]] (1949–1973) *[[Janet Akyüz Mattei|Janet A. Mattei]] (AAVSO Director 1973–2003) *[[Elizabeth O. Waagen]] (2003–2005) *[[Arne Henden]] (2005–2015) *[[Styliani ("Stella") Kafka]] (2015–2021) *[[Kathy Spirer]] (2022) *[[Brian Kloppenborg]] (2022–) }}
;Presidents <ref>{{Cite web |url=https://www.aavso.org/officers-aavso-1911-2014 |title=Officers of the AAVSO since 1911 |access-date=2021-07-09 |archive-date=2021-07-09 |archive-url=https://web.archive.org/web/20210709190323/https://www.aavso.org/officers-aavso-1911-2014 |url-status=live }}</ref> {{columns-list|colwidth=20em| *[[David B. Pickering]] (1917–1918) *[[Harold C. Bancroft Jr.]] (1918–1919) *[[Leon Campbell (astronomer)|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 Locke 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) *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. {{columns-list|colwidth=20em| * [[Leah B. Allen]] Charter Member <ref>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, [http://www.aavso.org/publications/ejaavso/v30n1/62.pdf AAVSO.org] {{webarchive|url=https://web.archive.org/web/20090109201922/http://www.aavso.org/publications/ejaavso/v30n1/62.pdf |date=2009-01-09 }} where her photograph from 1930 appears.</ref> * [[Joseph Ashbrook]] * [[Rosina Dafter]] * [[Radha Gobinda Chandra]]<ref>{{Cite web |url=http://www.aavso.org/aavso/history/webhist4.shtml |title=AAVSO: Part Four: The AAVSO and International Cooperation |access-date=2009-07-13 |archive-date=2009-06-08 |archive-url=https://web.archive.org/web/20090608033315/http://www.aavso.org/aavso/history/webhist4.shtml |url-status=live }}</ref> * [[Robert Evans (astronomer)|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]] * [[Giovanni Battista Lacchini|Giovanni B. Lacchini]] * [[Helen Lines]] * [[Richard D. Lines]] * [[Ben Mayer]] * [[Ruth J. Northcott]] * [[Arto Oksanen]] * [[Michiel Daniel Overbeek|M. Daniel Overbeek]] * [[Leslie Peltier]] * [[Lois Tripp Slocum]] * [[Peter Francis Williams]] * [[Ida E. Woods]]}}
==Publications== * ''AAVSO Alert Notice''. * [https://www.aavso.org/apps/jaavso/ ''Journal of the American Association of Variable Star Observers'' (JAAVSO)]. * ''AAVSO Circular'' was published from 1970 until 2000 and edited by [[John E. Bortle]].<ref>{{cite web|url=http://www.astroleague.org/content/john-e-bortle-2013-leslie-peltier-award-0|title=John E. Bortle - 2013 Leslie Peltier Award|access-date=26 September 2014|url-status=dead|archive-url=https://web.archive.org/web/20150620002810/https://www.astroleague.org/content/john-e-bortle-2013-leslie-peltier-award-0|archive-date=20 June 2015}}</ref>
==See also== * [[List of astronomical societies]]
==References== {{Reflist}}
==External links== *[http://www.aavso.org/ AAVSO website] *[https://www.aavso.org/vsx/index.php The International Variable Star Index] (VSX) *[http://www.aavso.org/history-aavso History of the AAVSO] *[https://web.archive.org/web/20090814151017/http://www.space.com/scienceastronomy/astronomy/stargazing_gamma_ray_000629.html Amateur Astronomy Reaches New Heights] Space.com, June 28, 2000 *[https://web.archive.org/web/20120309153022/http://www.skyandtelescope.com/news/4989341.html A New Foundation for the AAVSO] article in the January 2007 issue of ''[[Sky & Telescope]]'' magazine *[http://www.universetoday.com/2009/08/07/red-hot-news-possible-nova-in-sagittarius/ Red Hot News… Possible Nova in Sagittarius!] ''[[Universe Today]]'', August 9, 2009 * [http://www.aavso.org/100-years-citizen-science 100 Years of Citizen Science] (1 December 2010)
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{{DEFAULTSORT:American Association Of Variable Star Observers}} [[Category:Harvard University]] [[Category:Amateur astronomy organizations]] [[Category:Astronomy organizations]] [[Category:Variable stars]] [[Category:1911 establishments in the United States]] [[Category:Scientific organizations established in 1911]]