[ATM] smoothing the surface strange ronchi

[newsforfred@comcast.net]

greetings list

I have been polishing this mirror (4 inch f12) for some time with a tool 
from a previous mirror (4 inch f5). The mirror polished out well but I 
could not figure the mirror to a sphere. So I took the tool from this 
mirror and poured a new lap and was able to produce a good figure. 

Now after some tome testing it looks to be a bit rough and needs to be 
polished slower to smooth the surface. So my question is what stroke to 
proceed with? the mirror is fully  parabolic with under corrected edge 
and center.

My thinking is to go back to a sphere working tool on top?
 
while doing some test with a ronchi grating we notice some times the 
lines would converge and almost totally blur out each other. could any 
one try to explain this.

thanks
Tom


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