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Opinions on Ronchi images of 12.5" F3.8, Please

Started by Preston E, 08/09/2003 03:33PM
Posted 08/09/2003 03:33PM Opening Post
We have been working on an 12.5" f3.8 and after getting a nice
sphere polished out on the machine went on to figuring...
A batch of TOO soft pitch and and over eager helper resulted in the following images...after about 2 hours.
I believe we now have a slight hole in the center and a badly turned down edge of about .75 inches.
First image is almost null. With a 100 line/inch screen
Second image is +.200"
Third image is -.200" ...Cannot seem to get this to load???

Tester has the LED reflecting through the upper part of the
Ronchi screen and moves as a unit...

Thanks for any comments or corrective advice.

Attached Image:

Preston E's attachment for post 8227
Posted 08/10/2003 08:04PM #1

you may consider to join
There has been a lot of discussion re: mirror testing lately. You would get expert advice.