[ATM] The ultra thin 15.5

[vorblesnak <vorblesnak@peak.org>]

A series of odd circumstances has kept me away from grinding on the 
mirror since about mid October.  The last picture I posted to the upload 
site is basically where I am right now.  That last little dome shaped 
edge artifact is still there and is obviously quite deep, optically 
speaking.

I ran out of 220 back in October and ground for 5 and a quarter hours 
with 320 trying to get rid of  that last spot, but did not even phase 
it.  I have now purchased some 220 but I wonder, is it worth it?  That 
area is about 4 inches long by 1 inch wide, is the loss in thickness 
worth that much area gain?

My friend Chuck Lott says I gotta do it.  If the experiment is to be 
valid the entire surface of the mirror must be ground and polished.  
Craig Daniels reminded me that I will lose the outer 1/4 inch to my 
famous TDE polishing technique.  I'd like to prove him wrong, but has a 
point, and history is on his side.

So what do you think?  I could lose a 64th or better in thickness 
getting it out of there.

On a side note, the 16 came back from Alcoat.  It looks nice.  That one 
is 5/16ths thick, 8 pounds, f3.5.

David Davis
Toledo, OR 97391
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