Re: [ATM] Ronchi Question

[Jim Burrows <burrjaw@earthlink.net>]

At 2007-06-18 11:53 -0700, Dan Lago wrote:

>I have been working on figuring my mirror and I have found that when
>using the Ronchi test that I see three images of my mirror that are
>offset left and right by about 1/8"-1/4".  I have seen many pictures of
>Ronchi tests where this occurs so I assume that it is fairly common.  I
>have also seen pictures were it doesn't occur.  What causes this
>phenomenon and how do I get rid of it?

It's coming from diffraction - you are probably using a small 
source.  To see simulations of what views are likely from various 
tests:  Foucault, Ronchi, star, etc., download

         http://home.earthlink.net/~burrjaw/public/diffract.zip 
(2004-04-12, Win32, 374.6 k)


         -- Jim Burrows
         -- http://home.earthlink.net/~burrjaw
         -- mailto:burrjaw@earthlink.net
         -- Seattle N47.4723 W122.3662 (WGS84)


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