Date context
1571–1630
Teaching and astronomy
Kepler studied at Tübingen, encountered Copernican astronomy and later taught in Graz. His early cosmological model sought a mathematical order among planetary orbits. Access to better observations subsequently forced him to test such schemes against measured positions.
References: [1]
Tycho’s data and Mars
In Prague he worked with Tycho Brahe and continued using the observations after Tycho’s death in 1601. Discrepancies in Mars’s predicted position drove repeated revisions. Precise measurement and mathematical modelling were distinct, interdependent contributions to the resulting theory.
Three laws of motion
Astronomia Nova in 1609 presented elliptical orbits and equal areas in equal times. In 1619 Kepler related orbital periods to the sizes of orbits. These descriptive laws later supplied important constraints for Newton’s explanation in terms of gravitation.
Optics and astronomical tables
Kepler also studied vision, lenses and telescope optics. His Rudolphine Tables, published in 1627, brought observations and improved planetary theory into practical position calculations, connecting a revised picture of the heavens with the continuing work of astronomical observation.
References: [1]