What it looks like
Cepheus is a northern constellation close to Polaris, drawn as a king wearing a pointed crown. Its brightest stars form a shape like a child's drawing of a house. The constellation is the namesake of the Cepheid variables — a class of pulsating stars used to measure distances across the universe.
Brightest stars
Cepheus has no first-magnitude stars; its brightest, Alderamin, sits near magnitude 2.4 and marks one shoulder of the king.
| Star | Magnitude | Distance | Meaning |
|---|---|---|---|
| Alderamin (α Cephei) | +2.45 | 49 ly | The Right Arm |
| Alfirk (β Cephei) | +3.23 | 595 ly | — |
| Alrai (γ Cephei) | +3.21 | 45 ly | Shepherd |
| Delta Cephei | +4.07 | 890 ly | — |
| Mu Cephei (Garnet Star) | +4.08 | 2,800 ly | — |
Mythology and history
In Greek myth, Cepheus was the king of Aethiopia, husband of Cassiopeia and father of Andromeda.
The king of Aethiopia
Cepheus was the king of Aethiopia, married to the beautiful but boastful Cassiopeia. When his wife's pride offended the sea-nymphs and Poseidon sent a monster to ravage the coast, Cepheus consulted an oracle and was told to sacrifice his daughter Andromeda. He chained her to a rock by the sea, where Perseus found and rescued her. The whole family — Cepheus, Cassiopeia, Andromeda, Perseus and the sea monster Cetus — was placed in the sky together.
How to find it
Look for a house-shaped pentagon of stars near Polaris, between Cassiopeia and Draco, on autumn evenings.
- Find Cassiopeia's W, then look further toward the pole for Cepheus.
- Circumpolar from mid-northern latitudes — visible all year.
- Not visible from the southern hemisphere.
Key facts
- Abbreviation
- Cep
- Genitive
- Cephei
- Meaning
- The King
- Brightest star
- Alderamin
- Main stars
- 7
- Area rank
- 27th
- Best visible
- October
- Declination
- +70°
- Meteor showers
- —
- Neighbours
- Ursa Minor, Camelopardalis, Cassiopeia, Lacerta, Cygnus, Draco
Deep-sky objects
Cepheus contains the Garnet Star (Mu Cephei), one of the largest and reddest stars visible to the naked eye, and Delta Cephei, the prototype for Cepheid variable stars used as cosmic distance markers. The constellation is also home to the Fireworks Galaxy (NGC 6946) and the quasar Cepheus A.
Frequently asked questions
What does the constellation Cepheus look like?
Cepheus is a northern constellation known as the King, drawn as a house-shaped pentagon near the celestial pole, home to the famous variable star Delta Cephei.
What is the brightest star in Cepheus?
The brightest star in Cepheus is Alderamin, shining at around magnitude 2.45.
When is Cepheus best visible?
Cepheus is best seen from northern hemisphere during October.
What is the story behind Cepheus?
In Greek myth, Cepheus was the king of Aethiopia, husband of Cassiopeia and father of Andromeda.
Which constellations are near Cepheus?
Cepheus borders Ursa Minor, Camelopardalis, Cassiopeia, Lacerta, Cygnus and Draco.
Cassiopeia
Ursa Minor