[ATM] More Mirror Disasters!

["David Grennan" <dave@webtreatz.com>]

Hi all,

Last evening while working at figuring my 8 inch f6.3 I managed to get
something between the lap and the mirror which resulted in lots of tiny
(almost imperceptable) scratches all over my mirror.  Even though I tried
scrupulously to clean up every single grain from previous operations.  Hence
my first question.  Would you guys tolerate these tiny scratches and just
move on, should I go back to fine grinding, or is there a chance I can
polish these scratches out.

Now my second question.  After a period of using the classic parabolizing
stroke.  I was able to observe my mirror moving toward a parabola.  (I was
continuing with this stroke when I got all the little scratches).  After my
second session of parabolizing I fully expected to find my mirror closer to
the required section.  I thought if I was close enough I'd just forget about
the scratches and get the job finished!  However to my amazement the
foucault test shows me I'm back at a sphere again!!  I have no idea how this
occured.  I cold pressed for 1 hour before my second session of
parabolizing.  <aybe this wasnt enough.

So in summary my questions are.

1)  How (if at all) should I best deal with these fine sctratches.
2)  How could the classic parabolizing stroke bring my mirror back to a
sphere?

Confused :-0

Dave

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