Galileo measurement routes Sun Tech tycho


Tycho Brahe (1546–1601) was no ordinary 16th-century astronomer. Following an unfortunate duel he wore
an artificial nose, and he supposedly died from a burst bladder at a feast. More importantly, Tycho rejected
conventional academic career routes, eventually acquiring royal funding for a massive observatory on the island
of Hven, which is now a Danish heritage site on Swedish territory. He was particularly proud of his giant
quadrant, the brass quarter-arc astronomical device around two metres in height that can be seen in
the frontispiece illustration above.

Most of this picture is itself of a picture – Tycho and his snoozing dog belong to a mural painted within the
quadrant device, which is fixed to the wall and used to measure the precise position of a star as it passes by the
small sight on the top left. Behind the virtual Tycho’s outstretched arm lie illustrations of his observatory’s three
floors: the roof top for making night-time observations, the library with its immense celestial globe, and the basement devoted to carrying out experiments. An observer is just visible on the right, calling out to his
assistants who coordinate their measurements of a moving star’s time and position.

Tycho compiled the world’s most accurate and comprehensive set of star data. And, although Tycho
believed the Sun revolves about us, Galileo used his observations to confirm that the Earth indeed moves.