I might note that sometimes the links are changed and going to the senior page will often get the page you want. You might also want to look at the senior pages just to see more of what the page's owner has done in his pages.

       These sites were all found by the Google Search Engine looking for "Foucault Tester".

Bob Davy's slitless tester     A basic Richard Berry tester and a bonus of a .PDF file for a Ronchi Grating.
Robert Duvall's Tester    Nice description of how a tester works and construction of a Richard Berry tester along with info on Ronchi testing.
Dave Kelly's fancier tester    Made from aluminum stock and has a camera for viewing the test.
Chris Kovacs tester with a small telescope attached    Also has some not quite accurate shadowgrams (only shows half of the image) of the Foucault test.
An interesting one from Africa     It is a nicely done metal one with micrometer motions.
Berthold Hamburger's design     This page also includes some theory about testing.
Glen Bankston's tester and it's uses page    Just the basic tester with a good drawings on building it.
A fixed slit tester based on the Texerau book    What more can I say.
Eli Vande Voorde's Tester    Another Berry tester with a homemade measuring indicator. Also mentions basically the process of Wax Investment Casting, in this case, his delightful lead frog.
Bill Arnett's cheap tester (according to him)    Also has a lot of nice, but dark, photos of his mirror in the various stages of polishing. A nice study in what happens during figuring. Thanks Bill!
Yrjö Pullinen's Tester.     Mostly pictures of a complex tester but look anyway.

http://users.uniserve.com/~victorp/knife.htmhttp://users.uniserve.ca/~victorp/testing.htmhttp://www.jlc.net/~force5/Astro/ATM/Foucault/FoucaultTester.htmlhttp://www.fred.net/bdavy/FoucaultTester.htmhttp://zebu.uoregon.edu/~mbartels/mirror/mirror.htmlhttp://victoria.tc.ca/~rasc/foucault.htmlhttp://home.earthlink.net/~ckovacs/atm/foucault.htmlhttp://www.geocities.com/CapeCanaveral/9601/ftester.htmhttp://www.atmpage.com/foucault.htmlhttp://web.hal.com/users/elvey/foucault.htmlhttp://www.alltel.net/~microsys/astro.htmhttp://lamar.colostate.edu/~field/foucault/http://www.kolumbus.fi/pulliy/fouc.htmlhttp://www.mindspring.com/~davebevel/foucault/foucault.htmlhttp://www.efn.org/~elivv/spage5.htmlhttp://www.geocities.com/CapeCanaveral/9601/ronchi.htmhttp://zebu.uoregon.edu/~mbartels/caustic/caustic.htmlhttp://zebu.uoregon.edu/~mbartels/ronchi/ronchi.htmlftp://ftp.halcyon.com/pub/users/burrjaw/sixtests.ziphttp://home.att.net/~mikelhttp://www.seds.org/billa/tester/images.htmlhttp://www.stellafane.com/atm/atm_foucault_tester/atm_tester_main.htm

      Several of the testers use a television camera to allow the tester to see the optics under test without having to get into a delicate position. This is very easy to do! Just get a lens (or set the zoom lens) so that the mirror is pretty much filling the entire screen. Needless to say, you focus the lens on the mirror. You then just use the camera as your eyeball with the lens as close to the knife edge as you can get it and you will see the same thing as what you see if you put your eye behind the knife edge. Having the camera riding on the platform so that it moves with the knifeedge is the best way of doing it as you don't have to adjust the camera's position all of the time. You can also use the camera in place of your eye with the Ronchi test. The procedure is also useful for taking pictures with a 35mm camera. The testing is best done in a darkened room as that will allow for better contrast as a mirror not returning any light will indeed be dark.
 

Here's the home base for the TEX software for PC's This is a very nice piece of software although it runs in DOS.

      Many of the pages listed above contain other information including images or drawings of the image seen at the knife edge of the tester. Good Luck.