Re: [ATM] Additional phase contrast and Foucault images

["Stephen Koehler" <s.c.koehler@gmail.com>]

Dominic,

> Out of curiousity, what is the most significant defect you
> would exoect to identify?

I'm sorry, but I don't understand what you are asking, here.

My mirror appears very smooth under the Foucault test.  I know the
phase contrast test can show very faint markings, even on a smooth
mirror.  However, I have no idea how to quantify what it shows.  We
have tried, unsuccessfully, to find any features that match between
Dale's high-resolution interferometry of my mirror and the phase
contrast test.  From this, I conclude that we're unlikely to be able
to measure any thing the phase contrast test has shown.

> Also, you mentioned the mirror shown was coated. Does it by
> chance have one of these additional "protective" coatings?

It has a "standard" coating from Spectrum, which is SiO2 overcoated.
With so many layers, I think it is very difficult to know for sure if
the features are on the glass, aluminum, or overcoat.
-- 
Steve Koehler
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