Re: [ATM] Ain't got no shperometer

[ArtfulBodger <artfulbodger@earthlink.net>]

Francis J. O'Reilly wrote:

> A spherometer ... cannot come near to measuring with the accuracy
> necessary . It measures in ten thousandths, mot ten millionths.

Forgive me, I wasn't clear.  I'm talking about grinding, not 
polishing.  I just want to make sure the mirror is ground properly 
spherical before I put it on the pitch lap.  After that, yes, I'll 
need better measurements of everything.

I figured I'd take both mirrors (there are two, both 8", one f/4.5 
and the other f/5.5) through the polishing stage here at home, where 
I have no Foucault tester.  Then I'd do the figuring at the local 
mirror lab, where they have some pretty fancy equipment.

So anyway, at this stage, measuring in thenths is fine, no?

Pete

-- 
Artful Bodger
http://www.artfulbodger.net
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