Interestingly Alcor and Mizar was the first double star to be discovered and photographed and Mizar is the brightest star in the Ursa Major constellation, and Alcor is its fainter companion. Being so bright makes it easy to find. Click to enlarge Alcor and Mizar star chart In fact the Ursa Major used to be an open cluster but has since drifted apart to become the constellation we see today. Alcor is not orbiting Mizar closely ranging between 0.5 to 1.5 light-years. So on a planet orbiting Alcor, Mizar would appear as bright as Venus ! Through even a small beginner telescope, you can easily split Mizar into two visible stars: Mizar A and Mizar B. However, both A and B are actually spectroscopic binaries themselves—meaning their tight orbital pairs cannot be visually separated in standard amateur telescopes, making Mizar a four-star system all on its own!. With scientific class telescopes it was found that Mizar A, Mizar B and Alcor are all binary stars making Mizar and Alcor the first e...