Re: [ATM] Help with 50" scope

[Hugues.Laroche@ses-astra.com]

Hello Andy,

>An astro buddy of mine is doing a 50" f-8 Cass, has
>purchased a 50" pyrex blank from Vaughn Parsons of
>Intermountain Optics. Vaughn told him he can't grind
>and figure this monster, so my buddy is looking for someone
>to help him do the mirrors for the thing. I do
>large scopes and mounts (a 37" is in the works) but
>don't have any equipment to grind and polish
>optical components.

Well, I do not know if my experience can help, please
tell me. As you might know I am trying to make (when 
I have time, which is more and more seldom :-(( )
a 45" f/3.75 to become a newtonian. It was pre-curved,
but apart of this I have made the whole grinding by
hand with a 2/3 tool (and if the mirror's support hadn't
sucked that would have been OK). For the polishing
finally I had to admit that it was too hard, so I have
built a big machine for it (in wood, but I think you
have access to lathes and better tooling than I have).

>Any suggestions?

Although grinding by hand is possible, and as always gives
a very good feeling of the surface, in that size it is a 
good idea to build a machine. One big motor for the turntable,
one smaller for one or two eccentrics. I can send you pics
if you wish and if your maibox handles it...

Tell me. And, good luck in this huge project!

Hugues
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