Early Astronomy in the University of Michigan Collections


An astronomical quadrant is a graduated quarter of a circle used to measure the altitude of celestial bodies above the horizon. Usually, an arm would move over this partial circumference, which was graduated from 0° to 90°. The most accurate of these quadrans was the so-called quadrans muralis (mural quadrans). Tycho Brahe built a mural quadrant of two-meter radius in 1582, which became the most famous astronomical instrument of its kind in sixteenth-century Europe.

Brahe’s Astronomical Instruments

Brahe and Kepler

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