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Re: [ATM] Are these kits good? & Refractor Kits



Hello Richard

You have probably noticed I'm confused. You did mention some off list
communication.  

Is the Newport air-spaced design the "Mullet" design?
Do you have an Oslo file for Newport's air-spaced design?
Do you know if it was designed for visual or photographic use?


The Dimitroff/Baker design you mention is the one that I "cooked" to my
glass and f/D per Wyld's chapter (ATM 3 for me. Maybe you have the "New" ATM
books.) 
That chapter in ATM 3 by Wyld was my major source for guidance in
calculating my lens. If I drop that book on the floor it will probably open
to that chapter.

Jerry 





-----Original Message-----
From: Richard F.L.R. Snashall
The C and F lines do not cross in the aperture for the air-spaced Newport
design.

On the other hand, ATM 2 (the Wyld article) lists a Dimitroff/Baker design
similar to the Mullett design:

Surf      Radius    Thickness       Glass      Diameter
 STO    Infinity   -0.0860701                         6
   2      52.326       0.6237   BSC517645          6.12
   3     -32.265       0.2799                      6.12
   4     -32.265       0.4455    DF617366          6.12
   5    -145.701     88.81994                      6.12
 IMA   -32.25741                               1.579491

This design has a minimum focus at 550.627 nm and appears to be
corrected for spherical aberration coma at the e-line. It also
has the C and F crossing at the 85% zone (using Bausch and Lomb
glasses).  However, the difference is that this design is visually
better than the Newport prescription, even at the field edge. If
Schott F4 is substituted for the Bausch and Lomb dense flint, there
is some loss, but it still beats the Newport prescription.


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