Hi Fred, my way is better then RCOS IMHO.
RCOS, who sell a scope that costs so much money are in theory making the image quality suffer for convenience. The important thing for an RC is the mirror spacing. This paper talks about it a bit
http://www.heavensgloryobservatory.c...alignFINAL.pdf
So for an RC to work at it's best the spacing between the primary an d secondary should be a specific fixed length. A moving secondary obviously goes against this even though it is most convenient for a user.
In mine the spacing will remain constant and an extension tube is on the back of the scope bringing the camera to within ~4mm of focus. The FLI PDF focuser has 8mm of travel which will bring it to focus at the correct BF length..
Jason