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Explorations an Introduction to Astronomy Thomas T. Arny | ||||||||
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Chapter
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Chapter 1, Figure 19
Figure
1.19
Aristarchus
estimated the relative distance of the Sun and Moon by observing the angle
A between the Sun and the Moon when the the Moon is exactly half lit. Angle
B must be 90° for the Moon to be half lit. Knowing the Angle A, he could then
set the scale of the triangle and thus the relative lengths of the sides.
