ASTR 101 Lecture Notes - Lecture 4: Minute And Second Of Arc, Star Catalogue, Astronomia Nova
Document Summary
Galileo galilei (1564-1642, first modern scientist, in the sense that he pioneered the scientific method, four revolutionary discoveries (1609, moon not perfectly smooth. Contradicted the geocentric model, in which everything orbits. Earth, and hence church teachings: venusian phases. In 1609, galileo confirmed the heliocentric prediction: aberration of starlight, heliocentric model predicts stars to appear to be shifted toward earth"s direction of motion, some by as much as 20 arcseconds. Nearby stars will appear to be shifted more than faraway stars. However, by the mid-1800"s telescopes improved to the point that astronomers could, and did, confirm the heliocentric prediction. Tycho brahe (1546-1601: geo-heliocentrist (earth at center, sun orbits earth, planets orbit sun, best pre-telescopic astrometer, astrometry (not astronomy) is the practice of accurately measuring positions (right ascensions and declinations) of astronomical objects in the sky. Kepler would later use these data to develop and test his own, heliocentric ideas.
