This preview shows page 1. Sign up to view the full content.
Unformatted text preview: From the standpoint of apparent planetary motions as seen from Earth, this system is observationally indistinguishable from the Copernican model, yet maintains the fixity of the Earth. The latter belief was held by Tycho to the end of his life. A main reason was that he had been unable to detect the annual parallax of the fixed stars predicted by the Copernican model, despite the unprecedented accuracy of the observations carried out with his giant instruments at Uraniborg. Tycho could measure parallax down to 2 minutes of arc (1/30 of a degree). The failure to see parallax for fixed stars implied that they would have to be located hundreds of times farther away than Saturn, the outermost planet known at the time. Image reproduced from Hevelius' Selenographia. Before Tycho died he established Johannes Kepler as imperial mathematician to Rudolph II, the Emperor of the Holy Roman Empire. Tycho's data provided imperial mathematician to Rudolph II, the Emperor of the Holy Roman Empire....
View Full Document
- Fall '10