Hello,
I have just built a foucault tester. It is a slitless version, same as the one on the Stellafane website, using a green led. I was just reading about Holleran's double-pass foucault tester in the Sky and Telescope of August 1995. page 86. It is good info, but lacks details. Is there any other more detailed info on this setup? Or is this just one man's experiments , and has not become the standard foucault test in the ATM community?
Also, has anyone else tried this? Supposedly the foucault shadows are a lot brighter because of the double-pass. He said that the shadows of an f/8 mirror had the same apparent depth of those on a f/6.3 mirror of the same diameter. Any suggestions, pointers?
Thanks,
Brien Stratton
I have just built a foucault tester. It is a slitless version, same as the one on the Stellafane website, using a green led. I was just reading about Holleran's double-pass foucault tester in the Sky and Telescope of August 1995. page 86. It is good info, but lacks details. Is there any other more detailed info on this setup? Or is this just one man's experiments , and has not become the standard foucault test in the ATM community?
Also, has anyone else tried this? Supposedly the foucault shadows are a lot brighter because of the double-pass. He said that the shadows of an f/8 mirror had the same apparent depth of those on a f/6.3 mirror of the same diameter. Any suggestions, pointers?
Thanks,
Brien Stratton
