Bürgi, Joost

Bürgi, Joost or Jost,

1552–1632, Swiss mathematician and instrument maker. As the official clockmaker (1579–92) to Duke Wilhelm IV of Hesse-Kassell, he developed the first clock with a minute hand, as well as sextants and other astronomical instruments. Around 1588 he began using logarithmslogarithm
[Gr.,=relation number], number associated with a positive number, being the power to which a third number, called the base, must be raised in order to obtain the given positive number.
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 for conducting astronomical calculations and other computations; his invention of logarithms was independent from that of John NapierNapier, John
, 1550–1617, Scottish mathematician and theologian. He invented logarithms and wrote Mirifici logarithmorum canonis descriptio (1614), containing the first logarithmic table and the first use of the word logarithm.
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. Other scientific instruments designed and built by Bürgi include an astronomical clock (1591) based on the Copernican systemCopernican system,
first modern European theory of planetary motion that was heliocentric, i.e., that placed the sun motionless at the center of the solar system with all the planets, including the earth, revolving around it.
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 and several mechanized celestial globes. In 1604 Bürgi went to Prague as imperial clockmaker to Holy Roman Emperor Rudolf II, where he also worked with the astronomer Johannes KeplerKepler, Johannes
, 1571–1630, German astronomer. From his student days at the Univ. of Tübingen, he was influenced by the Copernican teachings. From 1593 to 1598 he was professor of mathematics at Graz and while there wrote his Mysterium cosmographicum (1596).
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