[ATM] another way of examining polish?

[David Margrave <david.margrave@gmail.com>]

I have a miror that I am in the process of polishing.  with the laser
pointer at 45 deg. method I can still see some scatter from the front
surface but it does not appear to vary as I move the pointer around
from center to edge.  On normal visual inspection it seems to be a
polished surface throughout.

I have noticed something when tesing.  I have the mirror on the stand
and use a large bright maglite flashlight to help position my tester
at the radius of curvature.  Overkill, I know.  I have noticed that
when I'm right at the ROC and the maglight is just at the threshold of
projecting an image of the filament into my eyes, that the mirror
takes on an appearance where I can actually see that the center is
hazier-looking than the edge.   In fact, this conforms to the same
position that I see a slight 'relief' in the mirror in the test.    
I'm just curious if there is a name for this method of examaning the
surface polish, because it seems easier to observe than with the laser
pointer method.

By the way I have been polishing with CeO, mirror-on-top, as I try to
get it spherical (this is  intentionally going to be a spherical
mirror for a special project).
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