Mizar is the second "star" from the end of the handle of the Big Dipper. With keen eyesight, or binoculars, this "star" instantly resolves into a double star, the two components of which are Mizar and Alcor. Alcor is at the top of this image, and Mizar is in the center. These two stars are separated by an estimated 1.1 light years, and have an orbital period of 5,000 years.
Note that Mizar has a second companion with a very small separation ("Mizar B"). While not visible in this image, Alcor also has a close companion, meaning that this is at least a four-star system. As a result, this is a quadruple star system.
Double Star Mizar
Date Taken:March 31, 2009
Location Taken: Conditions of Location:FWHM 2.5
Equipment Used:14.5" Ritchey-Chretien telescope, SBIG STL11000 CCD camera, Astrodon RGB filters, TCC, PIR, remote guide head used with Takahashi Sky90 for autoguiding, T-Point used for polar alignment (required for each imaging session due to my portable setup).
Processing Used:10x5 seconds luminance
Distance from Location:83 light years
Constellation:Ursa Major (the "large bear")
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