The constellation of Cepheus the King is north circumpolar and never sets for observers in the Northern Hemisphere.
The Mythology of Cepheus
Cepheus is a moderate-sized constellation named after a king of Ethiopia. His wife, Cassiopeia the Queen, is seated beside him in the sky. Their daughter, Andromeda, can be found on the other side of Cassiopeia. According to mythology, Andromeda was given as a sacrifice by her parents to the sea god Poseidon. But as a sea monster was on his way to devour the princess, the hero Perseus rides in on Pegasus the Winged Horse to save Andromeda from the sea monster. They eventually marry and Perseus becomes the new king of Egypt.
Finding Cepheus in the Night Sky
Locating the constellation Cepheus is generally a simple task. It is up every night in the Northern Hemisphere because of its proximity to the North Star, Polaris. Cepheus, whose borders extend almost all the way to Polaris, never sets. If you draw a triangle between the familiar constellations of the Little Dipper, the W-shaped Cassiopeia, and Cygnus the Swan (or the Northern Cross), inside that triangle you will find a house-shaped collection of stars. This pentagon is Cepheus.
The Stars of the King
The brightest star in Cepheus is Alpha Cephei or Alderamin. It shines at magnitude 2.45 in the bottom right corner of its house shape. Alderamin lies 45 light-years away. The other star forming the bottom of the house shape is magnitude 3.39 Zeta Cephei. It lies a much more distant 726 light-years away.
The star above Zeta Cephei that marks the top of the wall and the star of the roof is Iota Cephei at magnitude 3.50. It lies 115 light-years away. The other star at the top of the house shape that lies above Alderamin is the brighter magnitude 3.23 star Alfirk, or Beta Cephei. Alfirk is 595 light-years from Earth.
The star that marks the point of the roof in Cepheus is Gamma Cephei, or Errai, at magnitude 3.21. Like Alderamin, it lies 45 light-years distant.
Deep-Sky Targets in Cepheus
The Milky Way flows through the bottom half of Cepheus the King, however none of the star clusters found here are particularly well-known. One interesting area can be found just below a line drawn to connect the bottom of the house shape. This area is called IC 1396 or the Elephant Trunk Nebula. Through a telescope. first find the reddish star named Mu Cephei. It has been nicknamed the Garnet Star. This semi-regular supergiant varies in brightness from magnitude 4.5 to 3.5 over the course of two years. Below Mu Cephei look for a cluster of stars and nebulosity.
Another area of Cepheus that allows a combination view is NGC 7023, or the Iris Nebula. It can be found six degrees up from Alpha Cephei and three and a half degrees down from Beta Cephei, plus a little to the right from a line drawn between those two bright stars. Here you will find NGC 7023, a 7th magnitude star glowing from within its cocoon of gas and dust, creating a lovely reflection nebula.
The last deep-sky stop in Cepheus invovles two star clusters that lie approximately one degree away from Zeta Cephei and each other, forming a tight triangle. The brighter of the two is magnitude 7.7 NGC 7235. The other is magnitude 8.4 NGC 7261. These two clusters are the start of a trail of star clusters and nebula that zig zag in a trail toward Cassiopeia.
