▼ Ancient Greek astronomers, geographers and opticians.
▼ Representative works:
Astronomical classics, geography guide, four books.
▼ Ptolemy summed up the achievements of ancient Greek astronomy and wrote thirteen volumes of astronomy. The duration of one year is determined, the catalogue is compiled, the correction caused by precession and refraction is explained, and the calculation method of solar eclipse is given. He made use of a large number of observations and research results of Greek astronomers, especially Hippocrates, and systematically demonstrated various geocentric systems that explained the motion of celestial bodies with eccentric circles or small gear trains. Later generations named this geocentric system Ptolemaic geocentric system after him.
The magnum opus Astronomy 13 was an encyclopedia of astronomy at that time, and it was a must-read book for astronomers before Kepler's era. The eight-volume Geographic Guide is a description of his map of the world, in which the principles of astronomy are also discussed. He also wrote five volumes of optics, in which the first volume tells about the relationship between eyes and light, the second volume explains the visual conditions and binocular effect, the third volume tells about the reflection of plane mirror and curved mirror and the apparent diameter of the sun at noon and in the morning and evening, and the fifth volume tries to find out the law of refraction, describes his experiments and discusses the phenomenon of atmospheric refraction. In addition, there are works on chronology and astrology.