Review on Celestron Erect Image Prism: Enhance Clarity for Refractor and Schmidt Cassegrain Telescopes by Tim Harrington

I am very satisfied with this 45° righting prism for refractors. The whole article is made of metal. The thumbscrew is quite large and easy to tighten or loosen. The end that goes into the focuser has a 13/16" female thread which is 3/4" threads throughout, more than enough for attaching filters etc. The silver end that goes into the focuser, as shown in the advertisement image can be unscrewed from a diagonal of 45°. The image is viewed VERTICALLY, LEFT is LEFT and RIGHT is RIGHT as if looking through binoculars. It comes with caps on both ends to keep dust out. NOTE: One thing that caught my eye, the advert for this item didn't say it was a 45° diagonal prism, not even in the description. It wasn't until he got to my house that I saw a box that said 45° RATING PRISM. NOTE: For those who think this is a 90° diagonal prism, it's not, it's a 45° diagonal prism, so be aware. A NOTICE. This is the diagonal of the prism, not the diagonal of the mirror. From what I've read, Prism is better than Mirror. Only the electric mirror diagonals are the best, but expensive.