structural:scholar_edition
Renaissance and Early Modern

Renaissance scholars commonly practised astrology. Gerolamo Cardano cast the horoscope of king Edward VI of England, while John Dee was the personal astrologer to queen Elizabeth I of England. Catherine de Medici paid Michael Nostradamus in 1566 to verify the prediction of the death of her husband, king Henry II of France made by her astrologer Lucus Gauricus. Major astronomers who practised as court astrologers included Tycho Brahe in the royal court of Denmark, Johannes Kepler to the Habsburgs, Galileo Galilei to the Medici, and Giordano Bruno who was burnt at the stake for heresy in Rome in 1600. The distinction between astrology and astronomy was not entirely clear. Advances in astronomy were often motivated by the desire to improve the accuracy of astrology. Kepler, for example, was driven by a belief in harmonies between Earthly and celestial affairs, yet he disparaged the activities of most astrologers as "evil-smelling dung".

Ephemerides with complex astrological calculations, and almanacs interpreting celestial events for use in medicine and for choosing times to plant crops, were popular in Elizabethan England. In 1597, the English mathematician and physician Thomas Hood made a set of paper instruments that used revolving overlays to help students work out relationships between fixed stars or constellations, the midheaven, and the twelve astrological houses. Hood's instruments also illustrated, for pedagogical purposes, the supposed relationships between the signs of the zodiac, the planets, and the parts of the human body adherents believed were governed by the planets and signs. While Hood's presentation was innovative, his astrological information was largely standard and was taken from Gerard Mercator's astrological disc made in 1551, or a source used by Mercator. Despite its popularity, Renaissance astrology had what historian Gabor Almasi calls "elite debate", exemplified by the polemical letters of Swiss physician Thomas Erastus who fought against astrology, calling it "vanity" and "superstition." Then around the time of the new star of 1572 and the comet of 1577 there began what Almasi calls an "extended epistemological reform" which began the process of excluding religion, astrology and anthropocentrism from scientific debate. By 1679, the yearly publication La Connoissance des temps eschewed astrology as a legitimate topic.