[ATM] Ain't got no shperometer

[ArtfulBodger <artfulbodger@earthlink.net>]

What's the most accurate way to judge sphericity if you don't have a 
spherometer?  Is it the Sharpie test?

I'm sorry, thie is probably a FAQ.

I know there are other ways -- reading the bubbles between tool and 
mirror, judging the feel of the mirror sliding on the tool -- but 
they seem to need a good bit of experience.  Seems like the Sharpie 
test is closest to objective.  Or am I wrong, and is there a more 
precise test that I don't know about?

Gotta make me a spherometer, it's on The List, but my list is as long 
as yours is....

So.  Sharpie, yes?

Pete

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