Baader Planetarium Prism Diagonal T-2/90deg 32mm, Including 1.25" Eyepiece Holder and 1.25" Nosepiece

Instead of buying multiple dedicated 2 speed focusers for each scope that can cost as much as the scope itself does I use this Baader diagonal that isn't much more than a good diagonal itself is. I just pop it in the scope I am using that night then I have a very good diagonal and the ability for fine focus that really make a difference in the image quality especially as high magnification!.

I was really hoping for a correct image with this diagonal and feel kind of stupid because that's the primary reason I bought it, but I'm not going to penalize the item in a review for my stupidity. Just keep in mind that just because a diagonal uses a prism doesn't mean it provides a correct image.

Best prism diagonal out there now. Excellent construction as expected by Baader.

Best 1.25 Diaganol available...

A little online research will tell you that high-quality prism diagonals are the best for objects such as Jupiter, where resolution is key. The reflective coating is protected and never loses its reflectiveness; it does not have the potential loss of its correction as may occur with dielectric coatings. The only concern may be chromatic aberration with telescopes operating at less than f/7. I would include the Takahashi prism, 1.25 inch diagonal, on par with the Baader, but the Takahashi has a plastic backing, which in my experience eventually deteriorates around the screw-holes with resultant loosening of the plate. Note that Baader also makes a 2.00 inch prism diagonal. It's pretty heavy and here the Baader dielectric may be better (no loss of correction with the Baader methodology).