Cassiopeia

The bright "W" pattern of Cassiopeia is one of the more recognizable asterisms for mid-northern observers, for whom it is always above the horizon. We often think of it as a star pattern of fall since that is when it is climbing into the evening sky, but it can be seen any night of the year. The image here was taken in early May 2022. Gamma is the prototype of a class of eruptive variable stars; its light output varies irregularly by more than a factor of two. Eta is the bright star just over halfway from Gamma toward Schedar (Alpha). Eta is a well-known and easily observed binary star, one of many discovered by William Herschel. Herschel's binaries were among the first stars we could use to determine the masses of stars.