Use the iOptron 45° Erect-Image Diagonal to correct images horizontally and vertically when using an astronomical telescope as a spotting scope. Most telescopes are designed for astronomical viewing, and come with a star diagonal that will flip the image. While this is fine for the sky viewing, it is preferred to see terrestrial objects, such as birds, in their correct orientation. The Erect Prism Diagonal accomplishes such image correction and, at the same time, places the eyepiece at a convenient and comfortable 45-degree viewing angle. This diagonal fits into 1.25" focusers and accepts 1.25" eyepieces and accessories.