You're probably thinking of Mizar and Alcor, which are at the middle of the handle of the Big Dipper. This was used as a vision test in ancient times and in the

You're probably thinking of Mizar and Alcor, which are at the middle of the handle of the Big Dipper. This was used as a vision test in ancient times and in the middle ages. A fun fact is that it is actually six stars. Alcor is a binary star system and Mizar is a quadruple star system.