Alstar 125 90Degree Erecting Prism Optical Prism Inside Rather Than a Mirror which Makes Your Image Clear and Sharp

With this diagonal you can match the orientation of the star field with correct star maps and charts; It produces an image that is oriented properly; which means that the image is upright but reversed left to right, This is a great diagonal for daytime terrestrial use and night time astronomy applications for telescopes or spotting scopes, More comfortable viewing orientation as you observe from above; filter thread for any 1.25 inch filter; Accepts standard 1.25 inch eyepieces, High quality optical Prism inside rather than a mirror which makes your image clear and sharp, High quality optical Prism inside rather than a mirror which makes your image clear and sharp