On 10 September 1784 Edward Pigott detected the variability of Eta Aquilae, then known as "Eta Antinoi", and the first known representative of a class of variable stars later called Delta Cephei stars or, perhaps somewhat misleadingly, "Cepheids". This discovery occurred at a time when roughly a dozen variables were known, of which all but 6 were novae or supernovae. Read more