Cepheus is the 27th largest constellation in the night sky. Its brightest star is α Cephei with a magnitude of 2.5. It’s best seen from September to October at latitudes 90°N to 1°S. It’s recognizable by the shape of a distorted tower. It is located in between Cassiopeia and Draco.
Cepheus is most well known for its variable stars. It contains two main variable stars, δ Cephei and μ Cephei. δ Cephei’s golden-yellow color varies in brightness between magnitudes 3.5 and 4.4 about every 5.5 days. μ Cephei’s ruby-red color varies in brightness between magnitudes 3.4 and 5.1 over the course of about two years.
The class of variable stars called Cepheids are named after δ Cephei. The Cepheids are a class of variable stars that expand and contract making their brightnesses pulse.