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            | Nicholas Copernicus (1473-1543)
          disposed of the Earth as the Universe's center, by placing the Sun in
          the central position, with the planets (including Earth) revolving
          around the Sun. Although Copernicus tried to maintain some of the
          Ptolemaic epicycles, his work marks a new era of the "Heliocentric"
          theory. Tycho Brahe (1546-1601), financed by the King of
          Denmark, used a wall quadrant and sextant that measured
          star and planet locations accurately. This was modern equipment for
          this time. He noticed that the stars were farther than previously
          imagined. Johannes Kepler (1571-1630)
          using Tycho's records, developed 3 laws of planetary motion.
          Kepler's laws outline that the orbit of planets are elliptical with
          the Sun as the focus point; that planets revolve around the Sun over
          equal areas; and there is a mathematical relationship of how far the
          planets are from the Sun. Eyesight was still the most important tool
          that humans had to explore the sky. |