Re: [ATM] Calculate Astigmatism

[Woodchuck <djv@bedford.net>]

On Thu, 25 Mar 2004, john sherman wrote:

> Hi Dave,
>
> That's a good suggestion. If you make the slit two-dimensional by using a pinhole, then the test setup becomes more robust, requiring less rotations. What if you also replaced the knife edge with a 2D edge, a small, round spot? Could you then test for and measure astigmatism without having to disturb or rotate the mirror, the mask, the knife, or the light source? You could use the four-way mask described by Herb Kasler a while back to check both horizontal and vertical zones at the same time. Then rotate the mask only and you can check both diagonal zones at the same time.
>
> You like?

I dunno.  My experience is confined to straight knife-edges.  My brain
is confined to "geometric ray optics".  Have you conducted an experiment
with the "dot"?

Dave

_______________________________________________
ATM mailing list http://www.atmlist.net/