[ATM] SEC: UNCLASSIFIED:-Primary Mirror Retainers

[hermit at outofoptions.org (Ken Lowther)]

Mirror clips would be much simpler.

Ken

Quoting Andrew.Martyn@defence.gov.au:

> Was thinking last night about mirror cell design and all the various
> comments made recently about the pros and cons of RTVing mirrors to the
> cell. I have always RTVed my mirrors using 3 or 4 point cells as they have
> been full thickness mirrors of 10" or less and this has meant I have not
> had to worry about retaining clips and I have not seen any mirror
> distortion problems. However I was thinking of designs for a larger thinner
> mirror and thinking of the benefits of a non RTV design mainly in terms of
> the mirror not being distorted due to temperature changes changing the
> shape and size of the mirror cell relative to the mirror. However, I do
> like the idea of RTV in terms of mirror security.
>
> So I though why not use RTV a nut to the centre of the mirror back. Then
> through a hole in the mirror support pass a screw which locates into the
> RTVed nut. The hole through the mirror support would be big enough to let
> the mirror move around a bit but not big enough to let the screw head pass
> through. This arrangement would stop the mirror from falling out of the
> cell but not unduly restrain or apply a force on the mirror itself. Normal
> non RTVed supports would then be used for the bottom and side of the
> mirror.
>
> I am probably reinventing the wheel, but does anyone see any problems with
> this approach?
>
> Andy
>
>
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Hermit, holed up in Youngstown, Ohio