>>I would also imagine the thin corrector is most stressed when horizontal. Perhaps these are marginal considerations. >>
It is a misconception that a thin corrector, or for that matter any corrector, would be subject to stresses from bending. SCT and Mak correctors are essentially zero power windows, and you can bend and stress them all you want with no effect on the image. The reason is that whatever pretzel surface that you put on the front, you automatically put the exact opposite on the rear when you bend these elements (up to a point, of course). Thus the front and rear aberrations cancel out (do not confuse this with aberrations that can be polished in during polishing and figuring when the element is not supported properly). A mirror, of course, needs to be mounted totally stress-free because there is no opposite surface to cancel any stress induced errors.
Rolando
It is a misconception that a thin corrector, or for that matter any corrector, would be subject to stresses from bending. SCT and Mak correctors are essentially zero power windows, and you can bend and stress them all you want with no effect on the image. The reason is that whatever pretzel surface that you put on the front, you automatically put the exact opposite on the rear when you bend these elements (up to a point, of course). Thus the front and rear aberrations cancel out (do not confuse this with aberrations that can be polished in during polishing and figuring when the element is not supported properly). A mirror, of course, needs to be mounted totally stress-free because there is no opposite surface to cancel any stress induced errors.
Rolando
