[ATM] Zonal Correction

["Richard F.L.R. Snashall" <rflrs@rcn.com>]

Wanting to absent from my mind certain wounds suffered in the war
against Toxicodendron Radicans, with something simple (other than
looking up that Latin name in Wikipedia;-), I looked at an aspect
that I have long ignored.  What if you want, keeping physical
characteristics well in control, good C-F correction, but want
really good correction in the aperture for the e-line?  With the
five degrees of freedom offered by an air-spaced doublet, power,
achromatism, spherical aberration, zonal correction, and coma can
be corrected.

However, for some glass combinations, either the system is entirely
unrealizable (the air-space is actually negative), there is
significant ghosting, or, typically with larger spacing, there
is objectionable lateral color.

At 200 mm f/10:

    http://users.rcn.com/rflrs/dbl01-85.atm   ATMOS input file
    http://users.rcn.com/rflrs/dbl01-85.len   OSLO input file
    http://users.rcn.com/rflrs/dbl01-85.txt   TEXT prescription
    http://users.rcn.com/rflrs/dbl01-85.zmx   ZEMAX input file

and at f/15:

    http://users.rcn.com/rflrs/dbl01-86.atm   ATMOS input file
    http://users.rcn.com/rflrs/dbl01-86.len   OSLO input file
    http://users.rcn.com/rflrs/dbl01-86.txt   TEXT prescription
    http://users.rcn.com/rflrs/dbl01-86.zmx   ZEMAX input file

BTW: These are right out of the GSUM program, just shifting the
     separation until the 70% error was zero, inside shifting
     the correction wavelength to get C-F correction, inside
     selecting glass types.  I know, triple nested loop, but,
     as I said, it distracts the mind.

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