the order of days to months. Cepheid variables were discovered in 1784 by Edward Pigott, first with the variability of Eta Aquilae, and a few months later by John Goodricke with the variability of Delta Cephei, the eponymous star for classical Cepheids. Most of the Cepheids were identified by the distinctive light curve shape with a rapid increase in brightness and a sharp turnover.

Classical