Constellation: Ursa Major

The Big Dipper is an asterism in the constellation of Ursa Major. An asterism is a small group of prominent stars part of a larger group or constellation. Since you can’t really see the other stars of Ursa Major, I’ll just post this since it’s the best I can see from my rooftop.

This asterism is made with the help of 8 stars (from the end of the handle and around the bottom of the bowl) Alkaid, Mizar-Alcor, Alioth, Megrez, Phecda, Merak and Dubhe. You can see Alcor in the image above — it’s the faint star next to a very bright Mizar. The relationship and closeness of these two stars is what’s called a double star.

Mizar-Alcor are actually the first double star to ever be discovered through a telescope, in 1662; the first star to be photographed, in 1857; and the first star to be identified as a spectroscopic binary, in 1889.

Another cool fact to romanticise Mizar-Alcor a bit more: in Indian mythology, Mizar is known as Vashishtha and Alcor is known as Arundhati, the wife of Vashistha. In an ancient Tamil literature, also known as Sangam literature, Mizar-Alcor are mentioned as to signify the closeness of the bond in a married couple.

Even though Mizar and Alcor are ~1.5 light-years away from each other, they share a common proper motion across the sky whilst appearing to be close together.

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