American Association of Variable Star Observers (AAVSO)

The American Association of Variable Star Observers (AAVSO) is a nonprofit organization dedicated to the study of variable stars—stars whose brightness changes over time. Founded in 1911, it connects amateur and professional astronomers worldwide, collecting and analyzing observations to better understand stellar behavior. Members record star brightness at different times, helping track patterns and discover new phenomena. This collaborative effort enhances scientific knowledge of star evolution and variability, making it a vital resource for ongoing research in astronomy.