Mizar and Alcor are probably the most well known double star in the sky. Located in Ursa Major,it is very easy to separate Mizar from Alcor, even with the unaided eye.
Sidus Ludoviciana is the faint star between Mizar and Alcor. Mizar is the brightest one, which in fact is a binary system: Mizar A & B, with an angular separation of 14 arcseconds.
Photo taken with the dobsonian reflector Meade Lightbridge 16″, using afocal eyepiece proyection. Here we see 222 shots of 0.5 seconds of exposure stacked. No tracking, shift-and-add method.
Computer Physics Lab 