C

Callipus (fl. ca. 330 BCE)
  • Born in Greece.
  • He calculated the lengths of the seasons, starting from the summer solstice, to be ninety-two days, eighty-nine days, ninety days, and ninety-four days, respectively.

Giovanni Cassini (1625-1712)

  • Born in Italy.
  • He determined the rotation periods of Mars and Jupiter almost precisely.
  • He discovered the main gap in Saturn's rings and also four of Saturn's rings.
  • He and an assistant determined the best figure at the time for the distance between Earth and the Sun.

Giovanni Domenico Cassini IV (1625-1712)

  • Born in Italy.
  • He extended the knowledge of the Sun's periods and the periods of Jupiter, Mars, and Venus.
  • His laws describe the rotation of the Moon.
  • He was the first to record observations of zodiacal light.

Copernicus (Mikolaj Kopernik) (1473-1543)

  • Born in Poland.
  • He believed that the Ptolemaic theory was wrong.
  • He wrote that the sun is in the centre of the planetary system. This brought bitter hostility from the Church, thus forcing him to modify his views.