RE: ATM Foucault & Pinhole Camera?

["Frank Ward" <thewards@mindspring.com>]

James,

Your work in indeed fascinating. I hope you keep going.
Development >could< mean the removal of the Knife Edge from
the Fouchalt testing process! That would simplify the design and
fabrication of any video testing of optical surfaces. The operator would
be able to slip a pinhole (at the end of a tube) over the lens
of the CCD Video camera and measure the distance the lens itself moved as it
went thru the process from null to 100% zone. We would no longer
be limited to the 50% 75% and 95% zones. It would open up the
possibilities of full surface slope computation and you wouldn't need
lateral movement. You've really done it this time.

As for the artifact from 8:30 to 2:30 in your jpeg....I'm not
much of an electronics person but seem to remember that the light
inside the LED is from a "line" not a point. Could that line be retained
when it leaves the original pinhole which is then magnified by the
mirror giving a brighter light. (You could test by rotating the LED.)

Frank Ward
Atlanta, GA