Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. The Mizar-Alcor stellar sextuple system consists of the quadruple system Mizar and the binary system Alcor. Mizar is a quadruple system of two binary stars in the constellation Ursa Major and is the second star from the end of the Big Dipper's handle.With normal eyesight one can make out a faint companion just to the east, named Alcor or 80 Ursae Majoris. Alcor is of magnitude 3.99 and spectral class A5V.