Mu Cephei is a red supergiant or hypergiant star in the northern constellation Cepheus. It is officially named the Garnet Star; Mu Cephei is its Bayer designation, which is Latinized from μ Cephei and abbreviated Mu Cep or μ Cep. This star appears garnet red and is located at the edge of the IC 1396 nebula. It is a 4th magnitude star easily visible to the naked eye under good observing conditions. Since 1943, the spectrum of this star has served as a spectral standard by which other stars are classified.