American Association of Variable Star Observers

The American Association of Variable Star Observers (AAVSO) is a small, science-focused 501c3 non-profit organization headquartered in Cambridge, MA. Since its founding 1911, the AAVSO and its members have worked with the professional astronomical community to unlock the secrets of the cosmos through observations of variable stars and kindrid objects. Our current mission is to enable anyone, anywhere, to participate in scientific discovery through variable star astronomy.

AAVSO accomplishes this mission through collaboration with professional researchers, educational activities, and data stewardship. In 2022, our engagement with researchers yielded 300 peer reviewed publications and our educational programming reached 5,500 individuals. The majority of our effort involves curation of four databases including a photometric database with over 54 million observations, a variable star metadata database containing information on 2.2 million variable stars, a spectroscopic database with some 10,000 spectra, and an exoplanet database showcasing some 1,500 exoplanet transits.