Re: [ATM] Mirror cell design

["Jeff Anderson-Lee" <jonah@cs.berkeley.edu>]

mbyorick wrote:

>The mirror to which I previously referred is ~1.6" thick Pyrex, so it's
>not a particularly 'thin' mirror by present standards.  At any rate, my
>'observation', more formally stated, is the following: 
>For a mirror of ~10/1 diameter/thickness ratio (made from a
>similar-to-Pyrex material, which I believe would include most types of
>glass/other ceramics), the process of gluing the mirror, via a
>sufficiently compliant adhesive (e.g., RTV silicone), to a flotation
>cell (even a half-baked homemade one), results in star tests indicating
>negligible or non-existent observable astigmatism attributable to the
>mirror attachment method. 
>
Thanks for the update.

I do think RTV is a good way to go for many cases.  Especially given it 
is how the Pro's do it.  However their support systems also frequently 
incorporate separate planar and lateral support systems.  On the other 
hand most ATM advocates of RTV just say stick it to the cell and skip 
the lateral support entirely.  Thus I'd like to encourage folks to 
provide details on under what conditions that works (and when it 
doesn't) so we can all get a better idea on when we can get away without 
lateral support and when it might still be required.

[I have my own 16x0.875 inch f/5 plate mirror under way, and thus I am 
also selfishly motivated in this!]

Jeff

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