Re: ATM 11.2" F/2 Primary testing questions :)

["James Lerch" <jlerch1@tampabay.rr.com>]

----- Original Message ----- 
From: "James W. Burrows" <burrjaw@earthlink.net>
> 
> I found while testing my 10"f/2.6 RC cass primary that, as everybody knows, 
> Foucault was hopeless, and I don't think caustic was accurate enough.  I 
> used FPF (Focal Point Foucault) (before the days of webCams), which 
> required a lot of fiddling - mask hole pair readings averaged with single 
> hole readings, etc.  It leaves wire test or Hartmann (BTW, my Hartmann 
> program now asks for chip and pixel sizes; I'll upload it to my web site 
> when I redo the help file).

So the Harmann test will work for this mirror, that's good news!  I'll use the Ronchi  test for surface quality, and your Hartmann test for Quantative results.  Then I can tinker with the wire test, using your Hartmann results as a benchmark!  

James,  Thanks so much for making such a powerful testing tool available to us! :)

Take Care,
James Lerch
http://Lerch.yi.org/atm (My Telescope  Construction Webpage)