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Old 11-12-2008, 03:59 PM
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5ash (Philip)
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Join Date: Mar 2005
Location: Hunter valley. nsw
Posts: 1,117
Quote:
Originally Posted by skies2clear View Post
Wouldn't it matter how "thin" the mirror is in deciding whether to use a ring of silastic at the 60% zone or a proper 9 point flotation cell? It's easy to try the "ring" treatment and verify the performance on a star test. Making a proper 9 point cell will be a lot more work, but I confess, this is the way I'd be going to not take any chances, especially if you have a really nice optic. If it's so so, then maybe keep it simple.

Philip, how thick is your 13.1" mirror and what's it made of?

Cheers
Hi ,
the mirror is about 1" thick , What i dont understand with the flotation points for a cell is how they are fixed, i get the impression that some movement is necessary and think that silastic support at the right points might provide same?? Sidgwicks book"amateur astronomers handbook provides details on position of the points for a 9 point flotation cell.
regards philip
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