From: Mark VandeWettering 
To: Scott Berfield 
CC: atm{at}shore.net
Reply-To: Mark VandeWettering 


I can't imagine that having your mirror supported by anything flexible will
be at all desirable, if only because very small shifts can result in
miscollimation.
Stick with the tried and true (I'd probably go with a 9 point cell).

Scott Berfield wrote:

> Since I think I have a shot at actually finishing my mirror in this
> decade, my thoughts are turning again to the mirror cell. I have a full
> scale design for a 6 point cell all laid out and ready to go, but the
> more I think about it the more it seems like there should be a better
> answer than all that aluminum.
>
> I have searched the archives and found many references to using
> astro-turf type cells and these seem to be a very neat solution. The one
> complain I see anywhere is that the air flow around the mirror would be
> limited.
>
> I am currently polishing on a bed made from a Home Depot plastic
"grass"
> doormat. This is covered in stiff plastic "blades" which are
arranged in
> small circles. When polishing, even with considerable weight, the mirror
> does not shift appreciably on this mat. Like a bed of nails, the
> hundreds of support points add up to very even support.
>
> Since the mirror is held some distance off the substrate, and since the
> mat has regular perforations (app. 1/4" holes regularly spaced), it
> seems that airflow to the back of the mirror could be ensured by
> mounting the whole thing on a stiff perforated backing plate. A fan
> could be used to either blow or suck (not sure which would be better)
> air across from the sides or up through the middle. The mirror could be
> retained at the edge using clips or RTV. The whole thing would be light
> and cheap and very quick to construct.
>
> Are there flaws here I am missing?
>
> Scott
>
> -----------------------------------------
> Don't worry about people stealing your ideas. If your ideas are any
> good, you'll have to ram them down people's throats.
> - Howard Aiken
>
>
>

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