Cepheus: A constellation in the far northern sky, named after a king of Aethiopia in Greek mythology. It contains many notable stars, such as Alpha Cephei, Delta Cephei, and Mu Cephei, as well as various deep-sky objects, such as NGC 188, NGC 6946, and S5 0014+81.
Stars: Cepheus has several bright and variable stars, including Delta Cephei, the prototype of a class of pulsating stars that are used to measure distances in the universe. It also has some of the largest stars known, such as VV Cephei A and Mu Cephei, which are red supergiants with diameters over 1,000 times that of the Sun.
Deep-sky objects: Cepheus hosts a variety of nebulae, galaxies, and clusters, such as NGC 7354, a planetary nebula; NGC 6946, a spiral galaxy with frequent supernovae; NGC 7538, a star-forming region with the largest protostar; and S5 0014+81, a quasar with an ultramassive black hole.
Mythology and culture: Cepheus represents the father of Andromeda, who was chained to a rock as a sacrifice to a sea monster. He is depicted as a king holding his arms aloft in prayer. The constellation is also part of the Chinese Purple Forbidden enclosure and the Black Tortoise of the North. It has inspired the names of two US Navy ships and an update of the video game Stellaris.
Read about other constellations