· Show/Hide Description · (Product listings are below description)
A star diagonal is a mirror or prism system that lets you view objects that are at an angle (usually 90°) from the direction a refractor or catadioptric (Schmidt-Cassegrain or Maksutov-Cassegrain) telescope is pointing. This allows you to view comfortably when the telescope is pointed at, or near, the zenith (i.e. directly overhead) by looking straight into the scope in order to see overhead. You don’t have to twist your neck into an uncomfortable position to see objects over your head with a star diagonal. The image in a star diagonal is right side up, but will be reversed from left to right. A star diagonal cannot be used with a reflector telescope, nor is it needed with such a scope.