Re: [ATM] 40" mirror

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

Check out Hercules: http://www.runway.net/pilots/dan/welcome.html

Check out the Paracorr: http://www.televue.com/engine/page.asp?ID=230 
and it's performance graphs: 
http://www.televue.com/images/accessories/Paracorr%20Graphs.jpg

An f/3.5 mirror with a Paracorr (TM) will perform better than an f/8 
mirror without one.  I'm not sure how much faster than f/3.5 I'd be 
willing to go.

Also consider a thinner mirror.   Four inches of glass will almost never 
come to equilibrium.

Jeff Anderson-Lee

Jerry B. Hillman wrote:

>This mirror will be a truss tube Dobsonian.  I wouldn't even attempt
>something else.  The mirror will be made of pyrex, 40" in diameter and 4
>inches thick. solid, not slumped, not anything exotic. I know it will weigh
>about 400 pounds, but once any mirror is to heavy for me to lift, dealing
>with the weight becomes an engineering problem, not a physical strength one.
>It will be used exclusively for visual observation.  I have smaller
>telescopes that would be easier to do astrophotography with.
>


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