From: "Bob May" 
To: "atmlist" 
Reply-To: "Bob May" 


>>>
So with my mirror which if I am calculating it right is 22:1 then I could
glue the mirror to one point out of three (basic one point per triangle) on
a 27 point support and I would be okay?  what about while testing the
uncoated glass? I really don't want to glue it in place each time I test it
and have to cut it loose. Does the sling support contribute that much
astigmatism? Also, if rotating the mirror doesn't affect the astigmatism,
then could I discount it while testing if everything else checks out? And
then determine the effect of the sling when it is feasible to glue the
mirror to the support points?
Clear skies, Jerry
 >>>
I'd just not worry about gluing the mirror down in reality.  Test without
and you will know that you won't be any worse without gluing the mirror to
the supports after you get it aluminized. Please remember that the
distortions that are going to happen tend to be a lot less than the basic
surface error of the mirror itself. Also, when gluing a mirror to the
support, remember that you want to glue in such a fashion that the support
can expand and contract and not stress the mirror in the process.
Bob May
http://nav.to/bobmay
bobmay{at}nethere.com
NEW! http://bobmay.astronomy.net

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