[ATM] Second Thoughts on Mirror Support

[atmpob at yahoo.com (Dale Eason)]

Thanks Don,
The reason I asked was that much of the distortion for
a mirror in the horizontal position as you described
would be due to astigmatism.  The Foucault test is
blind to astigmatism.  So saying that the mirror
tested fine under these conditions does not confirm
that the cell did not induce astigmatism distortion.


Dale


--- Don D'Egidio <djd521@comcast.net> wrote:
> Dale,
> 
> It was the Foucault test done by our club guru. The
> reason the mirror had to be removed because it
> tested 1/2.51 wave. The mirror went back to
> Discovery and the replacement tested 1/4.85 wave.
> Both mirrors were very smooth. Our guru said it was
> up there with the smoothest he has seen, and he's
> tested many mirrors for the club.
> 
> Don
> 
> ----- Original Message ----- 
> From: "Dale Eason" <atmpob@yahoo.com>
> To: "The Amateur Telescope Makers List"
> <atm@atmlist.net>
> Sent: Monday, February 02, 2004 23:01
> Subject: Re: [ATM] Second Thoughts on Mirror Support
> 
> 
> > Don,
> > How did you do the testing?
> > 
> > Dale Eason
> 
> 
> _______________________________________________
> ATM mailing list http://www.atmlist.net/


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