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

I bought it to use my reflecting telescope for earth observation. Being new to telescopes, I didn't realize that the length of the prism increases the distance the focuser has to travel. With the prism in place, I couldn't focus even with the focuser fully inserted. The solution is to add a Barlow lens in front of the prism, which increases the focal length. With 2x Barlow magnification it now works exactly as intended. I'm only giving 4 stars because Celestron customer service just told me it doesn't work with my telescope. I figured out how to solve the problem myself.