Optical Instruments
353
The thin lens equation then gives the object distance for the objective as
( )( )
11
1
4.30 cm
50.0 cm
3.94 cm
4.30 cm
50.0 cm
qf
p
−
==
=
+
−−
−
The magnification by the objective is then
( )
1
1
1
4.30 cm
1.09
3.94 cm
q
M
p
−
=−
=+
and the overall magnification is
( )( )
1
1.09
1.75
1.90
e
mMm
++=
25.32
The angular resolution needed is
7
min
8
300 m
7.9
10
rad
3.8
10 m
s
r
θ
−
= ×
×
For a circular aperture
min
1.22
D
λ
=
so
9
min
m
1.22
0.77 m
rad
D
=
7
500
10
1.22
7.9
10
−
−
×
×
(about 30 inches)
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This document was uploaded on 10/20/2011.
 Spring '09
 Physics, Work

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