Designed for use with Twinstar reflector telescopes brand reflector telescopes rotates the image you see right up. As you may know, reflector telescope use mirrors to collect light, which means they usually project an image on the head. When you look into space, this is insignificant because there is no inverted head in space. However, if you want to use your telescope during the day to look at things here on Earth, you will probably want the image to be turned back in the right way. This eyepiece is compatible with any telescope or optical device that uses a standard 1.25" diameter eyepiece. Your image will be turned over and enlarged 1.5 times.