Published online by Cambridge University Press: 03 August 2017
Tycho Brahe's work set a new standard of objectivity in empirical science. Aiming at an observational accuracy of one minute of arc he had to introduce corrections of atmospheric refraction. This proved to be anything but trivial, mainly because Tycho adopted the traditional value of 3′ for the parallax of the sun. This parameter measured the size of the entire planetary system which Tycho refrained from vizualizing larger than conventionally accepted.