The AAVSO Archives
The Thomas R. and Anna Fay Williams AAVSO Archives
These data are formally published for the years 1900 to 2008. For a description of this data set, please click here.
Long-term observations of long period variable stars are essential to the determination of period, change in period, change in behavior resulting from mass loss and/or evolution, mode of pulsation (fundamental or overtone), internal structure, and phase at specific times for these stars.