Re: ATM Stellafane Report; Computer Assisted Digital Figure Analysis

["Peter John Smith" <pjifl@bigpond.com>]

In my opinion a good slit as source for a Ronchi test makes for cleaner
bands less worried by diffraction effects.  Nice if it is adjustable.  I
will never know why people are frightened to use a slit as a source.
Alignment is easy.

There was an article in Applied Optics about changing the light/dark duty
cycle of a standard Ronchi screen away from the 50%.  I experimented with
some wound wire screens which were wound at 50 % then etched away some of
copper wire by cleaning in Nitric acid but never really did a systematic
study of the effects of this.

The sinusoidal 'grating' and pinhole sounds interesting and seems to take
this much further.  Must try it.

All very interesting.


Peter Smith.