Re: [ATM] Flexed mirrors

[Dominic-Luc Webb <dlwebb@canit.se>]

On Sun, 13 Jan 2008, Bill Kelley wrote:

> The flex concept becomes very useful with the trend toward large, fast
> mirrors. On these conventional parabolizing by polishing to a smooth,
> zone-free figure is a bear of a problem for many atm workers.

When I confronted Alan Adler some years back about flexing a
fast mirror, it seemed clear we had differences in what we
perceived as fast. I perceive fast as F/1.0 to F/3.0. Alan did
not seem very optimistic at that time for these mirrors that
any of us would call fast. I was not too optimistic myself,
although, now that I have worked thinner slumped plate glass,
like 19mm thick and 300 mm diameter, maybe flex becomes an
option.

I know slumped glass flexes quite a bit on its own, which
makes testing a headache. But maybe flex can come to the
rescue if it can correct deformaties from sagging, etc. Of
course, those of us going for such mirrors are usually not
wanting a parabolic surface, but who knows, maybe someone has
some very fast folded visual system where this could help.

Dominic


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