The R1 Power Switch Star Diagonal is very similar to the S2. This is Refractor Ready because it includes the necessary OCS Optical Cell which is threaded onto the diagonal telewscope side body (seen in the photo) The OCS no longer says "low power" thogh it is the same optic we have always used. It is in fact the OCS A37.This must be used for refractors to reach focus with the power switch optics in a refractor. If you own both a refractor and an SCT, this is the proper choice for you to add to the Binotron -27 Ala Cart. Your Refractor will reach focus at 1.3X/2.3X/3X.
Remove the OCS and your SCT will focus at .66X/1.15X/2X. Includes both a refractor (non IVB) nose, and an SCT IVB Visual back and SCT nose with sprocket.