To: atm{at}shore.net
From: tkrajci{at}san.osd.mil
Reply-To: tkrajci{at}san.osd.mil


>From: "Mel Bartels" 
>
>>>>
>I have a 16x7/8 plate glass blank that I had Dan Cassaro pre-generate to
>f/5.  I went with f/5 because Plop seemed to indicate that I could support
>it with 18 points.  However later analysis shows that may not be so...
><<<
>
>Tom Krajci uses a 6 pt support for a similar sized mirror and it works
>wonderfully.  PLOP shows extremely small deformations.

Actually my mirror is about 1.5 inches thick (16 inch diameter,
pyrex)...but yes, the main point is that analysis by David Lewis (PLOP) and
Richard Schwartz (Star Fleet Engineering, also known as curmudgeon ATM)
said that six point support was 'good enough.'

And good enough it is.  I have yet to see any sign of mirror deformation
from the cell after four years of use.

Mirror is RTV glued to the six points.  No sling.  No problmes.

Tom Krajci
Tashkent, Uzbekistan

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