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Astronomy 263/264
Cross-Staff 1
Summary
The purpose of this lab is to show you how to measure the angle of a star
above the horizon, and relate the angle of Polaris above the horizon to
the latitude of the location from which you are observing.
Concepts
A cross-staff can be used to measure the angle between a star and some
other point. If we measure the angle between Polaris and the horizon,
we are measuring our latitude. The latitude
of any location on the northern hemisphere corresponds to the
angle between Polaris and the horizon.
If we are standing on the North Pole, the angle between Polaris and the
horizon is 90 degrees -- the latitude of the North Pole. If we stand on
the equator, at a latitude of zero degrees, Polaris is situated just
on the edge of the horizon. Lafayette's latitude is approximately
40 degrees so we find Polaris about 40 degrees above the horizon.
Last updated on September 25, 2000.
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