Go-astronomy logo

Cepheus Constellation
Constellation Cepheus the King of Ethiopia Star Map

Cepheus, the King of Ethiopia (Cep)

(see-FEE-us)


The Northern constellation of Cepheus, the King of Ethiopia, is best viewed in Fall during the month of October.

Cepheus is the 27th largest constellation. It's brightest star is Alderamin at magnitude 2.45. The boundary of the Cepheus constellation contains 3 stars that host known exoplanets.

Cepheus is a circumpolar constellation, so is visible year-round in the Northern hemisphere. Conversely, it is not visible in the opposite hemisphere.

5 protostars

      1. Pronunciation:
      2. see-FEE-us
      1. Meaning:
      2. King of Ethiopia
      1. Genitive:
      2. Cephei
      1. Abbreviation:
      2. Cep
      1. Constellation Family:
      2. Perseus
      1. Hemisphere:
      2. Northern
      1. Quadrant:
      2. NQ4
      1. Visibility:
      2. 90° N - 10° S
      1. Best viewing month*:
      2. October
      1. Area:
      2. 588 sq. degrees
      1. Size:
      2. 27th largest
      1. Circumpolar** (N=northern, S=southern):
      2. N circumpolar
      1. Right Ascension (avg):
      2. 22h 25m
      1. Declination (avg):
      2. 69°
      1. Brightest star:
      2. Alderamin  (2.45)
      1. Stars with planets:
      2. 3
      1. X-ray stars:
      2. 4 (2 binaries) stars


    Brightest Stars in Cepheus

    The 10 brightest stars in the constellation Cepheus by magnitude.

        1. Star
        2. Magnitude
        3. Spectral class


      Double Stars in Cepheus

      These are the brightest and easiest-to-find double, triple, and quadruple star systems in the constellation Cepheus . Also see all star clusters.

          1. Star system
          2. Magnitudes
          3. Type
          1. Beta Cephei
          2. 3.2, 8.6
          3. double
          1. Struve 2816
          2. 5.7, 7.5, 7.5
          3. triple
          1. Xi Cephei
          2. 4.5, 6.4
          3. double
          1. Delta Cephei
          2. 4.2, 6.1
          3. double


        Star Clusters in Cepheus

        The most notable and easy-to-find star clusters in the constellation Cepheus . Also see all star clusters.

            1. Star cluster
            2. Catalog #
            3. Cluster type


          Nebulae in Cepheus

          Notable and easy-to-find nebulae in the constellation Cepheus . Also see all nebulae.

          Orange hypergiant RW Cephei is the 5th largest known star in the universe at 1,500 times the size of the Sun.
              1. Nebula name
              2. Catalog #
              3. Nebula type


            Galaxies in Cepheus

            The most notable galaxies in the constellation Cepheus. Also see all galaxies.

                1. Name
                2. Alt name
                3. Type


              The King of the Northern Sky

              Cepheus is a constellation in the northern sky named after a king in Greek mythology. It is easily recognized by its distinctive house-like pattern formed by its five brightest stars. As one of the 88 constellations officially recognized by the International Astronomical Union (IAU), it plays host to a variety of celestial objects that are of interest to astronomers and casual stargazers alike.

              Historical Overview

              Among the 48 constellations listed by the 2nd-century astronomer Ptolemy, Cepheus has been a long-recognized constellation throughout history. It is named after King Cepheus of Ethiopia, a character in the Greek myth of Andromeda, who was the husband of Cassiopeia and father of Andromeda, both of whom are also commemorated in constellations.

              Location and Notable Features

              Cepheus is located in the fourth quadrant of the northern hemisphere (NQ4) and is visible at latitudes between +90? and -10?. The constellation is bordered by several other constellations including Camelopardalis, Cassiopeia, Cygnus, Draco, Lacerta, and Ursa Minor.

              The brightest star in Cepheus is Alderamin (Alpha Cephei), which is a white class A star located approximately 49 light-years away. Interestingly, due to precession, Alderamin was the northern pole star around 18,000 BC and will be again around 7500 AD.

              Deep Sky Objects

              Cepheus is home to several deep sky objects that are of great interest to astronomers. Among them is the Fireworks Galaxy (NGC 6946), so named because a significant number of supernovae have been observed within it. Also within the borders of Cepheus is the Garnet Star (Mu Cephei), a red supergiant star that is one of the largest visible stars in the night sky.

              Additionally, Cepheus contains a number of notable nebulae, such as the Iris Nebula (NGC 7023), a bright reflection nebula and Caldwell object that lies 1,300 light-years away, and the Wizard Nebula (NGC 7380), an open star cluster surrounded by a nebula that resembles a medieval sorcerer.

              Observing Cepheus

              In the Northern Hemisphere, Cepheus is a circumpolar constellation, meaning it never sets below the horizon for observers at higher latitudes. The best time to observe Cepheus is during the month of November when it reaches its highest point in the evening sky.

              The constellation's distinctive house-like pattern, formed by its five brightest stars, makes it relatively easy to locate in the night sky. It is found near the constellation Cassiopeia, which is shaped like a "W" or "M". The base of Cepheus (the bottom of the "house") points towards Polaris, the North Star.

              To observe the deep-sky objects within Cepheus, a small to medium telescope would be recommended. With such equipment, observers can witness the Fireworks Galaxy, the Iris Nebula, and the Wizard Nebula, among other stunning celestial sights.



              * Constellation shown for northen hemisphere skies. For the southern hemisphere, constellations appear rotated 180 degrees (upside-down and left-right reversed) from what is shown. Remember that seasons are reversed too - summer in northern latitudes is winter in southern latitudes.

              ** Circumpolar constellations are visible year-round in the hemisphere listed (and not at all in the opposite hemisphere).