In 1899, he separated the doublets in the Anastigmat to produce the four-element, four-group Unar lens.
12.
Double-meniscus anastigmats use widely separated positive and negative surfaces, generally thick meniscus lenses, to achieve a flat field.
13.
KH11 OTAs are of a three-mirror anastigmat ( TMA ) optical design ( sans the 3rd " tertiary " mirror ).
14.
In 1890, Rudolph designed an asymmetrical lens with a cemented group at each side of the diaphragm, appropriately named " Anastigmat ".
15.
With anastigmat image quality achieved, attention next turned to increasing aperture size to allow photography in lower light or with faster shutter speeds.
16.
In 1890, Rudolph designed an asymmetrical lens with a cemented group at each side of the diaphragm, and appropriately named " Anastigmat ".
17.
Virtually all good quality photographic lenses since circa 1930 are anastigmat corrected . ( The primary exceptions are deliberately " soft-focus " portrait lenses .)
18.
Paul Rudolph's Protar was the first successful anastigmat ( highly corrected [ for the era ] for all aberrations, including properly for astigmatism ) lens.
19.
The Protar was originally called the "'Anastigmat "', but that descriptive term quickly became generic and the lens was given a fanciful name in 1900.
20.
JWST's optical design is a three-mirror anastigmat, which makes use of curved secondary and tertiary mirrors to deliver images that are free of optical aberrations over a wide field.
