[ATM] Couder Masks and Zone Testing

[artbianconi@blast.net]

> I don't know how you can make a Couder mask with software.   I always used
> black paper or cardboard and an X-acto knife.
>
> Note that it is best when testing to isolate the mask from the mirror.
> That way you can adjust the mask position without disturbing the distance
> from the mirror to the knife edge.
>
> . . . Richard

Bob May shows some photo's on his website of him using an inexpensive PC linked "eye-
ball" camera to capture the reflected image of the mirror at COC. He then projects the image 
to a conventional CRT (TV set). Whether you are doing a Faucault test or a Ronchi, you 
have the option of capturing the image, saving it to appropriate media and then using the 
string of photos for checking your progress and adjusting your strokes. 

Gordon Waite and Mike Lindner have taken the idea a little further. At the risk of 
misrepresenting their creativity, I believe it goes something like this. . . . . . 

they cut the mask not to the  mirror but to fit the TV screen! Then they simply zoom in and 
out until the mirror image on the screen is sized to fit the mask! Then they do their tests.

Presto! One mask fits all !

Neat Huh?

Art

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