Search Loci: Convergence:
At first it seems obvious, but the more you think about it the stranger the deductions from this axiom seem to become; in the end you cease to understand what is meant by it.
In N. Rose Mathematical Maxims and Minims, Raleigh NC: Rome Press Inc., 1988.
Tycho Brahe's astronomical instruments
Title page of Tycho Brahe's Astronomiae instauratae mechanica. Brahe was the foremost astronomer of his time, particularly noted for his accurate celestial measurements. His radial observations were consistently correct within one second of arc. This accuracy was due in large part to the excellence of his self designed instruments, most of which are described in this book. For a complete translation of his table of contents and listing of instruments see http://www.kb.dk/en/nb/tema/webudstillinger/brahe_mechanica/.
An illustration from Brahe’s instauratae showing his great mural quadrant. This functioning quadrant was actually painted on the wall of his observatory, Uraniborg at Hven.