THE MURAL QUADRANT

OR THE TYCHONIC QUADRANT.

PORTRAIT OF TYCHO BRAHE, SON OF OTTO original: "O. F.", standing for "Ottonis Filius", BUILDER OF THE BUILDING This refers to Uraniborg, his famous observatory on the island of Hven AND OF ASTRONOMICAL INSTRUMENTS. IN THE YEAR OF THE LORD 1587, AT THE AGE OF 40.

This page serves as a title page for one of the most famous instruments in the history of astronomy: the Mural Quadrant. Unlike portable instruments, this was a massive brass arc bolted directly onto a north-south wall. By observing stars through a window as they crossed the meridian, Tycho could determine their positions with unprecedented accuracy. The portrait mentioned here is part of the iconic engraving showing Tycho pointing toward the stars while his assistants work in the background.