How to See Mizar and Alcor: Naked-Eye Double Stars in Ursa Major

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 ever six star system.

Are Mizar and Alcor True Binary Stars?

No, Mizar and Alcor are an optical double star rather than a true binary pair, though recent measurements show they are loosely gravitationally bound as part of a wider six-star system.

How do you find Mizar and Alcor

So now we have finished discussing Mizar and Alcor you can view the episode below to see the actual footage of the stars, which more accurately represents what you will see with the naked eye through a telescope. To see Alcor and Mizar for yourself first, find the plough or big dipper asterism that is in Ursa Major then look for the middle star off the handle zoom in on this star with a pair of binoculars or telescope and the binary star will be revealed.

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