Biomedical Engineering Reference
In-Depth Information
A
Galilean
Objective
Eyepiece
1
d
2
3
F
1
′
F
2
θ
θ
θ
′
4
h
1
2
3
4
f
2
f
1
′
B
Keplerian
Objective
Eyepiece
1
d
2
3
F
1
′
F
2
4
θ
θ
′
θ
4
h
3
2
1
f
2
f
1
′
Figure 12-7.
A.
A Galilean telescope, which consists of a positive objective lens and
a stronger minus eyepiece, produces positive angular magnification.
B.
A Keplerian
telescope, which consists of a positive objective and a stronger positive eyepiece,
produces negative angular magnification unless it is adapted with an inverting ele-
ment (such as a prism). The tube length of a telescope,
d
, is the distance between the
objective and eyepiece.
