NATS 1745 Lecture Notes - Lecture 2: Tychonic System, Geographical Pole, Naked Eyes
17 Jul 2017
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He wanted to determine the true model of planetary motion. He achieved his goal of measuring to one minute of arc. His aim was to confirm his own picture of the universe, which was that the earth was at rest; the sun went around the earth and the planets all went around the sun. 1563 discovered a planetary conjunction of jupiter and saturn (slowest planets). He found: the coordinates of the 1572 supernova (tycho"s star) remained fixed relative to other stars. Describe (briefly) how it should effect our view of the stars. A) the perceived shift of an object relative to its background due to the motion of the observer. B) the more distant the object, the smaller its parallax. The smallest angular shift (a) that tycho could measure was1/60th; thus if the earth moves a< 1/60th for all stars, and therefore (from the parallax equation) no star can be closer than 7000 au (ex 700x saturn distance)
