What is the size of the threading holding the visual back to my Schmidt-Cassegrain telescope? Is it the same for all Celestron SCTs?

The baffle lock nut is the back end of the C8 and C9.25; it is a 2 in x 24 thread.

On the C11 and C14 (and the EdgeHD 9.25), there is a reducer plate on the back over the baffle tube nut that has this same threading.

All but the oldest Celestron SCTs have the same threading accepting the visual back and can thus use the same accessories.

Updated 12/27/13