Ras Algethi (Alpha Herculis; a Her)

The brightest star in the constellation Hercules. It is a binary, consisting of a red supergiant M star with a sixth magnitude companion of spectral type F, which appears greenish in contrast. The secondary is itself a spectroscopic binary. The primary star is an irregular variable, its magnitude ranging between 3 and 4. The name, of Arabic origin, means "the kneeler's head".