[ATM] Foucault images

[Mike Lockwood <melockwo@uiuc.edu>]

Hi,

I have added some new images to my Foucault Testing Hall of Shame - 
now there is a "Hall of Fame" at the end of it.  Pictured there are my 
10" reference sphere and a 13.1" thin mirror I made recently.

One thing puzzles me.  In ALL of my Foucault images, there is a 
vertical texture that shows up which is due to something in the 
imaging system.  It is certainly not on the surface of the mirror, and 
it is there no matter what mirror is tested.

In fact, the texture sort of rotates as I rotate the eyepiece in my 3X 
scope (which I use on my Foucault tester).  That is, parts of it move 
left and right as the eyepiece is rotated, but the pattern itself 
remains composed of vertical lines.  Cleaning the eyepiece has reduced 
it, but it has not been eliminated.  The effect is not really apparent 
to the naked eye, but when my digital camera is used to take images 
through the scope, it can be seen.

To the eye, the mirrors are REALLY smooth, and any hints of the 
vertical structure move as you move your eye around.

Here's a link to the page:
http://bi-staff.beckman.uiuc.edu/~melockwo/mirror_making/foc_hall/foc_hall.html

Here's a shorter link to my home page - you can also reach the 
Foucault page by clicking on the link there:
http://bi-staff.beckman.uiuc.edu/~melockwo/index.html

Enjoy the photos - scroll down below the "Hall of Shame".  I have 
described them as completely as I can to indicate the differences 
between the images I captured and how it appears to my eye.

If anyone as thoughts on where the vertical artifacts are coming from, 
please post a message to the ATM list.  I suspect the fact that both 
the slit and the artifacts are aligned vertically is not a coincidence.

	Mike Lockwood

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