Constellation Cepheus (King)

Cepheus: IAU Constellation Map [150]


The constellation Cepheus revolves around the celestial north pole, followed by Cassiopeia on its eastern side and stands for Central Europe in the sky all year round. Despite its importance in Greek mythology, Cepheus is a less prominent constellation to the naked eye. In a dark sky you can see a figure that resembles a child's drawing of a house with a gable roof. The southern part of the constellation stands in a branch of the band of the Milky Way. The area is 588 square degrees and the center culminates on September 29 at midnight. Cepheus contains one of the most important variable stars for modern astronomy: delta Cephei. [9, 15]

Stars with Proper Names [154]
α Cep Alderamin, Alderaimin
β Cep Alfirk, Alphirk
γ Cep Alrai, Arrai, Errai, Er Rai
μ Cep Herschel's "Garnet Star"
ξ Cep Alkurhah, Al Kirdah, Kurhah
ρ2 Cep Al Kalb Al Rai
Data for constellation Cepheus [150]
IAU NameCepheus
IAU GenitiveCephei
IAU Abbr.Cep
English NameKing
Opposition25 August
Season (47° N)May … December
Right Ascension20h 01m 56s … 09h 03m 20s
Declination+53° 21' 12" … +88° 39' 50"
Area588 deg2
Neighbours (N↻)UMi, Dra, Cyg, Lac, Cas, Cam

Deep-Sky Object Descriptions


Constellation Cepheus
Constellation Cepheus: Illustration from «Uranometria» by Johann Bayer, copper engraving by Alexander Mair, 1603 [28]

Mythology and History

The constellation symbolizes Cepheus, the king of Ethiopia. He descended from Belos, the legendary Assyrian king. Cepheus' wife was the vain Cassiopeia, who boasted of being more beautiful than the nymphs of the sea. As punishment for Kassiopeia's vanity, the pretty princess Andromeda - daughter of this royal family in the sky - was chained to a rock by the sea to be sacrificed to the whale Cetus. The hero Perseus rode up through the air on Pegasus, freed Andromeda and married her. [82]


  • [9] «Drehbare Sternkarte SIRIUS» von H. Suter-Haug; Hallwag-Verlag, Bern
  • [15] «Hartung's Astronomical Objects for Southern Telescopes» by David Malin and David J. Frew; Melbourne University Press 1995; ISBN 0-522-84553-3
  • [28] «Uranometria omnium asterismorum continens schemata, nova methodo delineata aereis laminis expressa» Johann Bayer, Augsburg, 1603; DOI:10.3931/e-rara-309
  • [82] The Starry Sky: Cepheus by Deborah Byrd; Astronomy 9/95, p.63
  • [150] IAU: The Constellations, 11. Oktober 2020;
  • [154] Yale Bright Star Catalog, 15. Oktober 2020;