Tycho Brahe
- Galileo persecuted by Catholic Church
- Challenge to their authority
- cleared in 1992
Tycho and Kepler contemporaneous with Galileo f.4-28
- further advanced Copernican revolution
Tycho made very accurate naked-eye measurements
- Positions of stars and planets on celestial sphere
- celestial latitude and longitude vs. time
- Tycho’s instruments were very large -- why?
- to accurately measure small angles (i.e. Stonehenge, SAF)
- Accuracy 4 arcminutes = 1/15 degree
- about limit of naked eye
- nearest stars (lack of parallax) at least 15 x 57 AU’s distant
- actual distance at least 200,000 AU