Greek
Astronomy – Modern Foundations
•150BC
•Hipparcos - star
catalog (850, position and brightness)
•- better estimates of
size and distance of Moon
• R(earth)/R(moon)~8/3, D(moon)~60R(earth), D(sun) big
•- precession of Earth's
pole
•-epicycles and deferent
(used by Ptolmey) to explain retrograde motion of
planets
•150AD
•Ptolmey - worked out a
full geometric geocentric cosmology
•- accounts for
retrograde motion of planets
•- predicts planetary
positions
•- 55 concentric cosmic
spheres, all circular motion
•(size of Universe about
20000R(earth))
