Tycho Brahe (1546-1601) The Great Observer

• Constructed the largest and most accurate instruments for making astronomical observations.

• Motivated by money--he was astrologer to royalty.

• Recorded the motions of Mars for 25 years!

• Theorized that Mercury and Venus orbited the sun (halfway to heliocentric system).

• Others had made the same guess before him--he had much better data to back up his argument.

• Believed that the absence of stellar parallax proved that heliocentrism was false.