Not a good night for astrophotography. The moon was almost full, and images show low contrasts between stars and background sky. And the bloody mount suka suka anyhow drift in declination. In the end could only get 3 good images to stack, hence the noise.
Anyways, these are a famous pair of double stars in Ursa Major. They are not true binaries, given they are too far apart. Mizar itself has a true companion, but the 200mm f4L cannot resolve it. All 3 stars have been shown to be spectroscopic binaries.
Sidus Ludoviciana is an extra star in the background not related to the Mizar-Alcor system.
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