Re: [ATM] Use of bearings in (static) mirror cells

["James Lerch" <jlerch1@tampabay.rr.com>]

----- Original Message ----- 
From: "Jerry" <wa4guu@verizon.net>

> Referring to http://home.hetnet.nl/~artm/atm/articles/deformation.html

The assumption on this page is that the mirror is glued to the cell supports, 
and is relying on the cell supports to provide the equivalence of edge supports.

>Instead of shaping it like  ]  shape it like  I  .
>If Balanced I do not see how it imparts any deformation to the mirror as a
>result of tilt and the fulcrum being some distance from the glass.

If there were edge supports for the mirror, and the mirror was NOT glued to the 
cell, an argument could be made for balanced cell supports, but it may be a weak 
argument.

If the mirror IS  glued to the cell, and there are NO edge supports, then you 
would have to balance the cell parts AND the portion of the optic's weight 
supported by the cell parts.  For instance you would need to do something 
similar to this:

http://lerch.no-ip.com/atm/Balanced.gif (18KB)

Even in such a case, an argument can be made that the optic will be deformed, 
either from:
   A) Expansion / contraction of the glued on cell supports.
   B) The optic is only supported from its back while pointed at the horizon. 
Since the back of the optic is some distance from the optic's center of gravity, 
rotational and translational forces will be generated upon the optic.

Take Care,
James Lerch
http://lerch.no-ip.com/atm (My telescope construction,testing, and coating site)

"Anything that can happen, will happen" -Stephen Pollock from:
"Particle Physics for Non-Physicists: A Tour of the Microcosmos"

" Press on: nothing in the world can take the place of perseverance.
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