Re: [ATM] Faucault testing questions

[Guy Brandenburg <gfbrandenburg@yahoo.com>]

--- Mark Holm <mdholm@telerama.com> wrote:

> the shadows will 
> appear in different ways in opposite mask openings. 
> I had thought that, 
> either the zones went gray evenly, or that they both
> went gray from the 
> side that the knife edge was cutting, or perhaps
> that they went gray in 
> a way that depends on the local slope.  Nils shows
> that the dominant 
> effect, for a reasonably smooth mirror, has one side
> darken from the 
> center of the mask opening toward the edges while
> the opposite one 
> darkens from the edges toward the center.  I don't
> know if ray optics 
> predicts this, but I kind of doubt it.  Sure enough,
> when I went back to 
> testing, I saw that Nils analysis is correct.  The
> shadows really do the 
> strange thing that he calculated from diffraction
> theory.

That is definitely what happens!

Guy

Guy  Brandenburg
Washington, DC
My home page:
http://home.earthlink.net/~gfbranden/GFB_Home_Page.html
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