1. Mizar and Alcor
10 x 50
In the days before Herman Snellen introduced his eponymous eye-test chart, mag. +2.2 Mizar (Zeta (ζ) Ursae Majoris) and mag. +4.0 Alcor (80 Ursae Majoris) were used as an eyesight test: if you couldn’t see two stars, you knew you needed spectacles. They are,