[ATM] Figuring issues on 10 inch

["Douglas Arion" <darion@carthage.edu>]

I'm trying to finish up a 10" f/6....and using the Ross
Null test. On the bench, a 133 line Ronchi grating showing
3 lines across the mirror shows only the slightest bow...a
tiny bit undercorrected (by that measure). Star testing
shows the following: Inside focus there is a nice, sharp
diffraction pattern, comparable to those for 1/8 wave or
better inside of focus (as shown in the book...). Outside,
however, the pattern is, overall, fuzzy, with the
diffraction pattern hard to see. The central dark spot
looks darker out of focus than in, though both are the
almost exactly the same size. Suggestions?? 

Thanks,
Doug
_________________________________
Dr. Douglas N. Arion
Hedberg Distinguished Professor of Entrepreneurial Studies
Professor of Physics
Head Coach, Ice Hockey
Carthage College
2001 Alford Park Drive
Kenosha, WI 53140
262-551-5864
262-551-6208 (Fax)
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