Mizar

Second-magnitude star in Ursa Major, where it marks the middle of the handle of the Plough. Mizar and Alcor, a fourth-magnitude star, form a visual double star that the North American Indians called ‘the Horse and Rider’. Mizar itself was discovered to be a double star in 1650 by an Italian, Giovanni Battista Riccioli, and was the first star found to be double by using a telescope. Its brighter component was in turn the first spectroscopic binary to be discovered, by US astronomer Edward Pickering in 1889. The second component is also a spectroscopic binary.