From: "Tom Krajci" 
To: "'McHatten, Shawn'" ,
         
Reply-To: "Tom Krajci" 


>From: McHatten, Shawn [mailto:Shawn.McHatten{at}aliant.ca]

> Hey Tom
>       Umm? I don't understand. Why must the platforms be three points
(or >triangular). This 12 point designs looks perfect for three squashed
>diamonds. Each made up of three outer ring points and one of the inner
ring >points. Collimation bolts go in the middle of each of the diamonds.
>       Hmmm?? Now I got something ELSE!! to read up on :). I obviously
don't >understand mirror cell design :).

I'm still struggling to learn more also...and input from Richard, Nils, and
Steve have helped me.

I hesitate to use quadrilateral support platforms (square plates) instead
of triangles (3 points) or beams (2 points)...because if the quadrilateral
support on the back of the mirror warps...it will warp the mirror as well. 
If a beam or triangle warps...the mirror is not warped...collimation may
change, but no new stresses are put on the mirror.  (And you can re-adjust
for the collimation shift...so that's a minor problem.)  That's why I want
to use beams or triangles, not 4 or more point supports in a single entity.

At least, that's how I understand it in terms of 'mirror cell
theory'...kind of like the 'four color map theorem'...this is a basic
principle that I don't think I can violate if I want to make a properly
functioning mirror cell.

Or am I wrong on this?

Tom Krajci
Tashkent, Uzbekistan


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