Mixing Refractors and SCTs If you own both refractors and SCTs you quickly find out that you end up with duplicates of a lot of bits and pieces. Standard SCT parts won't fit on a refractor and normal 2" parts won't fit on an SCT. Fortunately, there is a wonderful piece of gear available for little money that lets you bridge the two. The Orion (and probably from other makers) Prime Focus Adapter. Orion Prime Focus Adapter I purchased one of these thinking it would just be an adapter to hold my T-ring when I shot through one of my refractors. Soon after it arrived I found out how versatile this piece was. The unit unscrews, with the 'head', or part that holds the camera adapter, and the barrell coming apart. Now here's the kicker; they thread together using a standard 2" SCT thread. This means your Prime Focus Adapter is now a bridging part. The barrel will fit in your refractor allowing you to screw on SCT parts and the T-ring part will screw onto your SCT or your SCT flattener-reducer. To use your diagonal on your refractor you might need a spacer (my AstroTech did). Find a friend who owns a lathe and ask him or her to cut you a quick aluminum (or nylon) spacer about .200" thick. A flattener/reducer is always nice to have around if you are into imaging. While the Celestron/Meade parts aren't optimized for for an f/7 refractor they do work nicely and will keep you going until the lottery win comes in and you can afford another one. One note, some focusers will NOT accept the Orion (or Antares) prime focus adapter's 2" barrel. I found a 2"->SCT adapter elsewhere that did fit my import Crayford. I also don't like my 2" barrels undercut for safety, the angled cuts at least allows the barrell to become 'cocked' at times which ruins the orthogonality of the optical train. Back to Ozzzy's Astronomy page