Re: ATM Foucault and Ronchi Testing

["Bob May" <bobmay@nethere.com>]

Wish I could point you to pages but I haven't really seen any that deal with
problems like this.
FWIW, if the Ronchi Grating isn't fully transparent it will cause a halo
problem.
For the diffraction lines on the Foucault tester, I sometimes get them (and
a bunch of other silliness) when I use my eye at the KE but when I put the
camera there, the problems seem to go away.  You might want to try a
camcorder or other TV camera (the $40-$50 security cameras work very nicely
for this and most don't mind dedicating a camera to something like this -
they also work nicely afterwords for a backup viewer for your motorhome!
Bob May
http://nav.to/bobmay
bobmay@nethere.com
NEW! http://bobmay.astronomy.net