Cepheus

Cepheus, constellation in the northern sky, at about 23 hours right ascension and 70° north in declination. It is shaped like a box with a triangle on top. The brightest star, Alderamin (from the Arabic for “right arm”), has a magnitude of 2.5. The star Delta Cephei gave its name to the variable stars called Cepheid variables. Cepheid variables have a close relationship between their period of variability and their luminosity and thus have been...