Re: [ATM] The Flexed mirror

["Bob May" <rmay@nethere.com>]

In a talk with Bob Goff several years ago the topic of what work
he did at Meade and Celescton came up on the subject of building
their SCT scopes.  He mentioned that they did a vacuum on the
corrector plates and they had put plaster under teh plates so
that they'd be to a particular radius when vacuumed.   This
allowed them to just apply a vacuum and not worry about the exact
RC of the glass as it just pressed against the plaster when it
had enough vacuum under teh glass.  This allowed them to quickly
and accurately form the glass to the right curvature without
having to be finicky about it.  Problems that were popping up
were that they allowed contamination of the plaster surface and
that kept the glass from mating solidly against the plaster
without getting bumps in the surface to be ground, whicch then
were ground away by the polishing process and thus making an
incorrect shape on the surface of the glass.
Bob May
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