Re: ATM Astigmatism

[Rick Maillet <bucko_62@yahoo.com>]

--- Ricardo Dunna <rdunna@infolink.com.br> wrote:
> 
> Donīt agree. Move ronchi grating in and out near
> around focus and
> look. If lines appear to rotate a bit or change
> direction, itīs
> astigmatism.

 Ok, If I read this right, then, I now have
astigmatism on my mirror, because when last I checked
mirror for sphere, I saw that very effect
happen...when close to ROC but inside, if I move to
outside,my lines would shiftopposite to what they
where. (((slightly off straight to the left inside-too
slightly off straight to the right outside))).

Now my thought process has it that this problem was to
do with not being perfectly square onto the optical
axles, with the tester, (slitless, moving
source)thereby making the shift because of the
movement inside to outside off axles.

Now, is that not the case....seems if the light comes
to a point at ROC, all light will be opposite outside
of ROC as to what it is inside of ROC, therefore
causing this shift, does that make sense, or should I
try something else to determine for sure whether or
not astigmatism does exist on the surface of this
mirror. 
                                    Rick
As far as I know, I have done everything to avoid this
situation, but with my luck.........better to find out now.

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