Transcription: Hipparchus, circa 190 to 125 BC. Hipparchus, in addition to being a mathematician, was also the most important of the ancient astronomers. He determined the length of the tropical year, the time taken for the earth to revolve around the sun, and the lengths of the seasons. He also tried to measure the size and distance of the moon. He introduced the notion of geographical length latitude and longitude, which are the coordinates for determining position on the surface of a sphere. He was the first to realize that the Earth's axis of rotation moves slightly in relation to the stars. This effect ... File Comment Made in Intimate Arts
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