ALCOR

(from Arabic, faint one), also called 80 Ursae Majoris, star with apparent magnitude of 4.03. The ability to see the dim star Alcor with the unaided eye may have been regarded by the Arabs (and others) as a test of good vision. Alcor makes a visual double with the brighter star Mizar in the middle of the handle of the Big Dipper (Ursa Major); the pair have also been called the Horse and Rider.