Observing Variable Stars

"The American Association of Variable Star Observers (AAVSO) is a worldwide, nonprofit, scientific and educational organization of amateur and professional astronomers who are interested in variable stars. Its purpose is to coordinate, collect, evaluate, analyze, publish, and archive variable star observations made largely by amateur astronomers, and to make these observations available to professional astronomers, researchers, and educators." Click here to visit the AAVSO website.

I have been a member of the AAVSO since 1975.  Being part of this exciting collaboration between amateur and professional astronomers has been an extremely rewarding experience.  Director Janet Mattei once said, "To me, an observation of a variable star is not a number, not a statistic. It's something very much alive. I see the brightness estimate and imagine the observer's face light up as he or she looks at the star through a telescope."  Every time I find a new variable star, or make a new estimate, that's exactly how I feel.  Thanks to the AAVSO for making it possible for me to make a useful contribution to the scientific community!  I greatly appreciate the support and encouragement it has given me over the past 30+ years.

In November 2005, during a stretch of unusually clear weather, I observed the Cepheid variable TU Cassiopeiae frequently.  Then, assuming a period of 2.14 days, I combined my observations into a graph showing the magnitude of the star as a function of time within a single period. The result is shown above. Click here for more information about TU Cas.