Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Epsilon Canis Majoris is the second brightest star in the constellation Canis Major, and one of the brightest stars in the night sky. It has the Bayer designation "epsilon" despite being the second brightest and not the fifth brightest star in its constellation. It has the traditional name Adhara. Adhara is a binary star, about 430 light years away from Earth. The main star possesses an apparent magnitude of +1.5 and belongs to the spectral classification B2. It has a surface temperature of 25,000 K and emits a total radiation equal to 20,000 times that of the Sun. If this star were at the same distance as Sirius, it would appear 15 times brighter than the planet Venus. This star is also one of the brightest known extreme ultraviolet sources in the sky.