Cepheus constellation
Cepheus (the King) is a constellation in the northern sky, best seen in the evening in October. Its brightest star is Alderamin (magnitude 2.44). Cepheus covers 589 square degrees and is the 27th-largest of the 88 constellations.
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Detailed star map of Cepheus
Facts
| Latin name | Cepheus (genitive: Cephei) |
|---|---|
| Abbreviation | Cep |
| Meaning | the King |
| Area | 589 square degrees (27th of 88) |
| Location | right ascension 22.2 h, declination +72° |
| Visible from | latitudes 90° N to 1° S (whole constellation) |
| Best month | October (at about 9 pm) |
| Brightest star | Alderamin |
| Stars brighter than magnitude 6 | 94 |
| Named stars (IAU) | 4 |
| Messier objects | none |
| Neighbors | Camelopardalis, Cassiopeia, Cygnus, Draco, Lacerta, Ursa Minor |
How to find Cepheus
From 40° N (the USA, southern Europe, Japan) Cepheus is circumpolar: it never sets and is visible all night, all year, highest in the north about 58° above the horizon in October evenings. From 35° S (Australia, South Africa, Argentina) it stays below the horizon. The months before and after (September and November) are also good: then it is up a couple of hours earlier or later.
Cepheus borders Camelopardalis, Cassiopeia, Cygnus, Draco, Lacerta and Ursa Minor.
Stars of Cepheus
Cepheus has 94 stars brighter than magnitude 6, the limit of the naked eye under a dark sky. These are the brightest:
| Star | Designation | Magnitude | Type | Distance |
|---|---|---|---|---|
| Alderamin | α Cephei | 2.44 | A7V | 49 ly |
| Errai | γ Cephei | 3.21 | K1III-IV | 45 ly |
| Alfirk | β Cephei | 3.23 | B1IV | — |
| — | ζ Cephei | 3.35 | K1.5Ib | — |
| — | η Cephei | 3.43 | K0IV | — |
| — | ι Cephei | 3.52 | K0-III | — |
| — | δ Cephei | 3.75 | F5Ib-G2Ib | — |
| — | μ Cephei | 4.08 | M2-Ia | — |
| — | ε Cephei | 4.19 | F0IV | — |
| — | θ Cephei | 4.22 | A7III | — |
| — | HR 285 | 4.25 | K2II-III | — |
| — | ν Cephei | 4.29 | A2Ia | — |
Printable Cepheus map and outline
A black and white version for printing and a plain outline of the Cepheus figure, useful for school projects, worksheets and learning to recognize the shape.
History
Cepheus is one of the 48 constellations listed by Ptolemy in the Almagest (2nd century AD). Its official boundary was drawn by Eugène Delporte for the International Astronomical Union in 1930.
Questions about Cepheus
What is the brightest star in Cepheus?
Alderamin, at magnitude 2.44, about 49 light-years away.
When can you see Cepheus?
Cepheus is best seen in the evening in October. The whole constellation is visible from latitudes between 90° N and 1° S.
How many stars are in Cepheus?
94 stars in Cepheus are brighter than magnitude 6 and can be seen with the naked eye under a dark sky; 4 of them have official IAU names.
What does Cepheus mean?
Cepheus means “the King” in Latin. Its abbreviation is Cep and the genitive, used in star names such as α Cephei, is Cephei.
