®
M o d e l N o . O S - 8 5 1 5 B
E x p e r i m e n t 1 3 : T e l e s c o p e
35
Experiment 13: Telescope
Purpose
In this experiment, you will construct a telescope and determine its magnification.
Theory
Figure 13.1
An astronomical telescope consists of two convex lenses. The astronomical telescope
in this experiment will form an image in the same place as the object (see Figure
13.1).
The lenses are thin compared to the other distances involved, which allows the Thin
Lens Formula to be used:
(eq. 13.1)
where
f
is focal length,
d
o
is the distance between the object and the lens, and
d
i
is the
distance between the image and the lens.
The magnification,
M
, of a two-lens system is equal to the product of the magnifica-
tions of the individual lenses:
(eq. 13.2)
Set Up
1.
Tape the paper grid pattern to the screen to serve as the object.
2.
The +200 mm lens is the objective lens (the one closer to the object). The +100
mm lens is the eyepiece lens (the one closer to the eye). Place the lenses near one
Required Equipment from Basic Optics System
Bench
2 Convex Lenses (+100 mm and +200 mm)
Screen
Paper grid pattern (see page 45), or a 14 × 16 grid of 1 cm squares
d
o1
-d
i2
d
i1
d
o2
Object
Image
Lens
+200 mm
Lens
+100 mm
Eye
1
f
---
1
d
o
-----
1
d
i
----
+
=
M
M
1
M
2
d
i1
–
d
o1
----------
⎝
⎠
⎜
⎟
⎛
⎞
d
i2
–
d
o2
----------
⎝
⎠
⎜
⎟
⎛
⎞
=
=
Summary of Contents for OS-8515B
Page 6: ... Basic Optics System About the Experiments 6 ...
Page 26: ... Basic Optics System Experiment 9 Apparent Depth 26 ...
Page 38: ... Basic Optics System Experiment 13 Telescope 38 ...
Page 42: ... Basic Optics System Experiment 14 Microscope 42 ...
Page 44: ... Basic Optics System Experiment 15 Shadows 44 ...
Page 46: ... Basic Optics System Telescope and Microscope Test Pattern 46 ...