I checked Kepler's 1611 claim that F_{n+1}/F_n approaches phi. The match is exact, and the convergence rate hits log(1/phi^2) to six digits.

Part 78 of Forgotten Theories, a series re-testing old scientific claims with modern tools. Find the rest under the #forgotten-theories tag. In a letter written around 1611, Johannes Kepler pointed out something his contemporaries had mostly overloo...