The Constellation Directory


"The King"


By IAU and Sky & Telescope magazine (Roger Sinnott & Rick Fienberg) [CC-BY-3.0], via Wikimedia Commons

Abbreviation: Cep
Genitive: Cephei
Constellation family: Perseus
Nearest constellations: Camelopardalis, Cassiopeia, Cygnus, Draco, Lacerta, and Ursa Minor
Right ascension: 22.52h
Declination: 71.59°
Visible between latitudes: +90 and -10°
Square degrees: 588
Luminary: Alderamin (Alpha Cephei)
Named stars: Alderamin, Alfirk, Errai
Notable deep sky objects: NGC 188, NGC 6939, NGC 6946 (Fireworks Galaxy), IC 1396


Cepheus is not a bright constellation, but it is visible throughout the Northern Hemisphere. It is best seen in October.


Cepheus by Johannes Hevelius

By Johannes Hevelius [Public domain], via Wikimedia Commons

In Greek mythology, Cepheus was the King of Ethiopia, husband of Cassiopeia and father of Andromeda. Cassiopeia was narcissistic and claimed that her beauty surpassed that of the Nereids, or sea nymphs. Poseidon was angered by her statements and attacked the coast of Ethiopia. Cepheus consulted an oracle who told him the only way to calm Poseidon was to sacrifice his daughter Andromeda to the sea monster Cetus. Following the oracle's advice, Cepheus and Cassiopeia chained their daughter to a rock by the coast where Cetus could reach her.

However, before Andromeda could be devoured by the sea monster, Perseus flew by on Pegasus. He saw Andromeda and rescued her by killing the sea monster.