Re: [ATM] Calculate Astigmatism

[bchilders@everestkc.net]

A bit off thread...and I'm not quite sure how it would work but as you are describing rotating the knife edge the image of a zone plate (a type of camera lens with concentric circles, looks like an airy disk) popped into mind.   I'm wondering is something like this ever used in mirror testing. 

-Buck
 
----- Original Message -----
From: "Donald \"Don\" Ware" <mimas@charter.net>
Date: Wednesday, March 24, 2004 2:20 pm
Subject: Re: [ATM] Calculate Astigmatism

> ----- Original Message ----- 
> From: "Woodchuck" <djv@bedford.net>
> To: "Stephen C. Koehler" <koehler@securecomputing.com>
> Cc: <atm@atmlist.net>
> Sent: Wednesday, March 24, 2004 2:52 PM
> Subject: Re: [ATM] Calculate Astigmatism
> 
> 
> > A certain precision in construction of the KE apparatus would 
> be needed,
> > though, otherwise a "re-zero" step with the central zone would 
> be needed.
> > It would seem easier to construct a rotating knife edge than a 
> rotating> mirror.  Maybe it could be done optically, with a Dove 
> prism?
> You would also have to rotate the Couder screen and any lateral 
> shift during
> the rotation might impact the results although this would be 
> small.  If
> you're using James Lerch's RTAFT, the digitization of the zones is 
> stillfixed on one axis, although I presume this could be changed, 
> (what say you
> James?).
> 
> Don Ware
> Hollis, NH
> http://webpages.charter.net/dware1/
> 
> 
> 
> _______________________________________________
> ATM mailing list http://www.atmlist.net/
> 

_______________________________________________
ATM mailing list http://www.atmlist.net/