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Re: [ATM] Non Achromatic Eyepieces
Going a bit futher, I found a 3 lens solution that almost works.
The four (8 inch f/15) prescriptions are:
32x 31x 29x 30x t G D
1 72.4554 72.551 77.376 46.829 0.8 N-BK7 8.4
2 -43.0795 -42.756 -42.469 -63.292 E0.05
3 -43.4886 -43.2211 -42.828 -61.39 0.6 F2 8.4
4 -179.064 -178.75 -157.4 741.43 80.0
5 18.24 21.3 11.88 10.2 0.8 S-BAM12 3.0
6 -2.503 -2.494 -2.624 -2.569 0.2 N-KZFS11 3.0
7 4.238 4.327 3.988 3.519 0.4 S-TIM3 3.0
8 19.38 23.3 11.82 10.05
BFL 37.24077 33.59642 36.91623 36.23080
iRoC 43.53 33.6 250.4 13.54
The radii of the five lenses differ, but the thicknesses (the air-space
between the N-BK7 and F2 lenses is given as an edge thickness), glasses,
and diameters are the same for all four prescriptions. The back focal
length and best photopic image radius-of-curvature are given below each
prescription. Optimization was over a field of about 1/3 inch diameter.
The prescriptions differ in the method used to determine the doublet.
Prescription 32x used the GeeWyld program with the Schott catalog values
of nd, F-C dispersion, and Abbe numbers. Prescription 31x also used the
GeeWyld program, but simply worked to a minimum focus of about 550 nm.
Prescription 29x used ZEMAX to photopicly optimize the OPD of the doublet.
Prescription 30x also used ZEMAX, but photopicly optimized the OPD of the
whole system, allowing all surface radii to change (the thicknesses were
fairly well constrained). Optimization of the full system included a
goal effective focal length. (To preclude nilpotence of the doublet,
prescription 30x also had a goal clear aperture of 2.8 inches for the
first triplet surface.)
The photopic Strehl ratio of the four systems was determined, first
measuring the doublet and then the full system.
32x 31x 29x 30x
doublet 0.580 0.579 0.560 0.566
system 0.952 0.953 0.942 0.957
Incidently, did anyone else notice that Schott now has a ZEMAX .agf format
catalog on their website?:
http://www.us.schott.com/optics_devices/english/products/flash/abbediagramm_flash.html
Now ZEMAX itself triples the size; I guess adding a few catalogs
together, but
appears to utilize the Schott source directly (see the catalog comment
in the
first line)...
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