Re: [ATM] The 16 inch Ultrathin ronchi pics

[vorblesnak <vorblesnak@peak.org>]

Dale Eason wrote:

>We need to know the LPI of the Ronchi grid. 
>
>  
>

Sorry.  That is my home made 50 LPI.  Done in Windows Paint and printed 
on a Lexmark T630 on overhead film.

>However I can see that you are getting close to what I
>got.  Look at my interferometry report and you will
>see the two bumps in the center.   I think you are
>also seeing the 1/2 wave surface primary astig as
>well.  That is the slight twist  as you go through
>ROC.  
>
>  
>
Actually either of the one line shots show a slight twist and the exits 
are offset just a bit.  That is the ronchi line jump spoken of when 
looking for astigmatism.  I have no good excuse for it, but if anybody 
has an idea for the cause of it I am all ears.  I have gone over my 
notes and I do not see anything about any kind of a fancy stroke.  I did 
work the 70% zone a bit.



>Dale Eason
>  
>

David Davis
Toledo, OR 97391
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