[Raytrace] wavefront analysis

[Tom Wicker]

Regarding the slight difference in P-V OPD in the text
and graphic windows: I tried John Sherman's suggestion
and at 100 points the two agreed to the precision
displayed.  Thanks.

I read the optics reference that I downloaded with
OSLO to get some insight into why autofocus for
minimum spot size gives different P-V OPD results than
that for min OPD (for a perfect spherical wave they
would be the same).  It seems that min spot size
samples and calculates the RMS for transverse
aberation in the image plane, and min OPD (as the name
says) calculates optical path difference from a
reference sphere and gives the RMS for a sample from
that.  So I guess it shouldn't be surprising that they
are different in some cases. As I said before, a file
I set up for a 25" f6 mirror shows no difference
between the two, whereas the 22" f4.5 does. This seems
to indicate that aberation and/or astigmatism (both
are smaller with the f/6) cause the difference. This
makes me wonder which is more relevant to knife edge
testing. I would guess transverse aberation, ie., min
spot size. Anyone have any input on this? Can anyone
recommend a good optics text that goes into this?

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