Re: [ATM] Mirror cell design for "web-back" lightweight mirror blank

["Jeff Anderson-Lee" <jonah@cs.berkeley.edu>]

Off-hand, I would probably suggest going with an 8 point cell  and put 
the support points on the ribs.  A support radius of between 0.447 R 
(refocused) and 0.547 R (non refocused) should do.  Join adjacent pairs 
of support point with bars, and join one pair of bars with another bar 
to get down to three support points.

However United Lens seems to be a top notch optical company, so perhaps 
if you called their customer service number they might be able to 
recommend something more specific.

Sounds like a "fun" piece to play with.

Jeff Anderson-Lee
Sacramento, CA

Nate Jones wrote:

>Hello ATM list,
>
> 
>
>After a long break from telescope making (first mirrors made were 10" f/6
>and 6" f/5) I recently purchased a 16 inch "web-back" Pyrex blank from
>United Lens Co.  I am currently polishing and it is coming along nicely.
>
> 
>
>I realized there may be an issue using a standard mirror cell design as
>there are ribs in the back (eight of them) leading to a central ring of
>glass, putting the support points under areas that are in the pockets.
>
> 
>
>Has anyone used these blanks, and if so what type of mirror cell was used?
>
> 
>
>Thanks,
>
>--Nate
>
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>  
>

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