Re: ATM Corrector plate flex????

[Aplanatic@aol.com]

Jerome:

>>>>>>>>
Close  tolerances of the corrector are essential for optimal performance.
Surely the plate must flex under the above conditions and underperform.
<<<<<<<<

For small deflections both sides of the Schmidt corrector bow about the same amount.  The corrector is a phase plate, in other words it is only the thickness profile of the corrector that matters, not the slope of each surface (to first order, anyway).  When the corrector is bowed or otherwise deformed, the thickness profile remains constant (again, for small deflections) and therfore does not change the optical behaviour of the plate.  A mirror, of course, does not benefit from this cancellation.

Dave Rowe