[ATM] Mirror back from coaters with scratches

[Hiroyuki HIKITA <hikita@tkb.att.ne.jp>]

Hi all!

Lots of wandering through the ATM archives and sheer luck,
my second attempt to make a 6" F6 mirror came out very well
with a smooth surface and Waveerror P/V 1/20 Lambda.

Two weeks ago I sent out my second mirror to the coaters.
Today my 6inch F6 mirror came back from the coaters.

Lesson: NEVER use a cheap coater just to save $50...

The mirror came back with several S shaped scratches about
2"x1" in size.

So my question is:
1) How obvious are scratches this size under the Foucault test?
   Could I have missed it under the knife??

2) Is there a quick way to tell if the scratches went all the way to the glass?

# Hiroyuki HIKITA <hikita@tkb.att.ne.jp>
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