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[ATM] Complexity
Bob May wrote:
> Yes, a 2" EP does make a nice bit of sense for a finder. Gives a
> much better eye relief than some smaller EP does.
So, revising an old eyepiece design that uses 2 OTS BK7 lenses
(Melles Griot LPX209 planoconvex and LDX115 isoconvex), for a
12x combination:
Surf Radius Thickness Glass Diameter
...
10 2034 16.62039 39.47323
11 -49.657 4.2 N-SF1 50.8
12 49.657 16.8 N-BK7 50.8
13 -49.657 1.29 50.8
14 Infinity 10.6 N-BK7 60
15 -62.247 5.46 60
16 62.247 18.4 N-LAF34 60
17 -62.247 4.2 N-SF1 60
18 Infinity 52.695 60
IMA Infinity 7.591469
Ten lenses, fourteen air-glass surfaces... on the other hand,
the ER is over two inches with a 4 degree FoV (~50 deg APoV),
four of the lenses are OTS (read $, too), and a spherometer
isn't really needed, since all the remaining surfaces can be
figured against those four lenses.(;-)
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