Re: [ATM] another way of examining polish?

["Bob May" <bobmay@nethere.com>]

Yep, you just figured out one of the test methods for finding out if the
mirror is fully polished out.  What is happening is that the pits are
producing diffraction edges and that causes the light to be seen at all near
on-axis angles.
I've done that test when the grinder thinks that he's fully polished out and
disagrees with my assesment.
That you have the frostiness in the middle indicates that you have probably
been using a stroke that is too long, both with grinding and probably with
polishing the mirror.  As a result, you have a hole in the middle.
Bob May
bobmay@nethere.com
http://nav.to/bobmay
http://bobmay.astronomy.net

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