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Quadrant. Engraving of an astronomical quadrant used by the Polish-German astronomer Johannes Hevelius (1611-87). The instrument is so named because its arc is a quarter of a circle. It was used for measuring the altitude of a star, that is its angular height above the horizon. Hevelius built one of Europe's finest observatory in Gdansk, Poland, during the 1640s. Hevelius was one of the last astronomers to make many observations without a telescope. Despite this, he made accurate observations of stars, comets and feat- ures on the Moon. He gave detailed descriptions of his equipment in Machina Coelestis, but they were accidentally destroyed in a fire in 1679.
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