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Re: (ATM) Chasing Shadows


Hi Carl

1   Foucault shadows only have sharp borders for fast (ie < f4.5) 
mirrors. Usually the shadows look quite gentle. photos have a habit of 
increasing contrast.

2. Sounds like you have a very mild turned edge, if you can see a 
diffraction ring all around your mirror.

3. the ronchi grating is not so good for evaluating  TDEdge because of 
the inherent diffraction effects at the edge of the mirror.

hope this helps

mark