From: Charles Oliveri 
To: atm{at}shore.net
Reply-To: Charles Oliveri 


Hello all,

I have recently begun my journey into ATM. With my 8” f/8 “well underway”
(ok, so far 2 hours rough grinding and several months prior of plotting and
planning -- followed by yet more plotting and planning) and a cheesy 50mm
f/4 refractor built from scrounged parts, a new project beckons to me…

A friend got at auction a box of optics/photography equipment. What
interested me were the 5 clear optical glass filters 4.25” by .25”. Only
one of them is marked: the word “CLEAR” with a triangle inscribed in a
circle to the left. The rest are all unmarked.

I would like to make an f/4 or f/5 newt, mostly to learn to figure a fast
mirror. Sagitta would be between.064” and .052”, depending. Is this
reasonable in a .25” thick blank? What would be the best way to proceed
with grinding? Using another filter as the tool or pour a tile tool (should
I try to find .5” tiles?)? Should I build up the thickness of both tool and
mirror before I start grinding?

Advice appreciated!

Thanks,
Charles

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