Evolution of the Astronomical Eyepiece - Brayebrook Observatory

EVOLUTION of the ASTRONOMICAL EYEPIECE
EYEPIECE EVOLUTION - 1610 to 1990+
eyepiece types in order of origin
No. NAME DATE APPARENT EYE CRITICAL COMMENTS
OF FIELD RELIEF f/no
ORIGIN
66 FLEISCHMAN 1977 50˚ 1.13 4 1-1-2-1: First computer autooptimisation
for Zeiss.
67 MODIFIED 1980 60˚ 0.1 5 1-1 fluor ite lens w ide a ngle
a symme tric
RAMSDEN
R ams den, with ze ro rectilinear
distort ion, desi gn e d b y
W al t er Ka s tne r.
68 KALLIPLAN 1980 25˚ 0.8 15 2-2 Symmetrical achromatic, flint
concaves aspherized; designed by
J.D. Greenwood.
69 NAGLER I 1980 82˚ 1.2 4.5 2-1-2-2 ultra-wide angle with Smyth
lens, designed by Al Nagler.
70 TUSCON 1982 40˚ 1.0 6 2-2-2 compensating flat field
ASPHERIC
designed by Clarke having aspheric
eighth surface.
71 CLARKE 1982 50˚ 1.0 6 1-1-1 compensating flat field
Huyghenian with Barlow lens.
72 NAGLER II 1984 82˚ 1.0 4.5 2-1-2-1-2 ultra-wide angle with Smyth
lens, modified Nagler I to reduce spherical
aberration of the exit pupil.
73 MEADE ULTRA1985 84˚ 1.5 4 2-1-2-1-2 ultra-wide angle with
WIDE ANGLE
Smyth lens similar to Nagler II,
marketed by Meade.
74 PRETORIA 1985 50˚ 0.7 4 2-1-2-1 coma correcting flat field
eyepiece designed by
Klee & McDowell.
75 PANOPTIC 1988 68˚ 0.7 4 2-1-1-2 wide-angle manufactured by
Takahashi and others.
76 WIDE 1990 50˚ 0.5 4 1-2-2 modified asymmetric Plössl
ORTHOSCOPIC
with a dditional fiel d lens; manu
f actur ed by Takahashi and othe rs.
77 WIDE SCAN 1990 65˚ 1.2 5 2-1-2 & 2-2-1-2 redesigned
astroplanokular, manufactured by
Takahashi and others.
78 LE 1990 52˚ 1.2 5 2-1-2 & 2-2-1 redesigned
astroplanokular, (Long eye relief)
ma nufactured by Takahashi and
o t h e r s .
79 LV 1990 52˚ 20mm 5 2-2-1-2 redesigned astroplanokular,
(Lanthanum) using L antha num glas s.
Manuf ac tur ed by Ta ka hashi
and othe r s.
80 SW ASPHERIC 1990 67˚ 0.75 4 2-1-2- 1 Ta kahashi super-wide
angle havi ng moulded aspheric
meniscus eye lens.
81 LEITZ 1990 88˚ & 90˚ 0.7 3.5 2- 1-1-3 Lei tz- Wetz lar hyper- w i d e
a ngle de sign having a moulde d
pl astic meniscus shell bonded
into the concave surface of the
e ye double t.
(iv)