Claudius Ptolemy's Accomplishments

Claudius Ptolemy was born C. 100 CE. The size and content of his literary production suggest that he lived until about 170 CE. He was a Greek descent, mathematician, geographer and Egyptian Astronomer. Nothing much is known about Ptolemy’s life apart from what can be anecdotal from his writings. The Major Astronomical work he did was title the Almagest which was completed about 150 CE and contains reports of Astronomical observations that Ptolemy had made over the preceding quarter of a century. Almagest, was called by Ptolemy the mathematical collection because he believed that the heavenly motions could be explained in mathematical terms. Ptolemy was primarily responsible for the geocentric cosmology that prevailed in the Islamic world and
in medieval Europe. In his work called Planetary Hypotheses he proposed what is now call the Ptolemaic system. It is a unified system in which each heavenly body is attached to its own sphere and the set of spheres nested so that it extends without gaps from Earth to the celestial sphere. Ptolemy taught later astronomers how to use quantitative observations with recorded dates to revise cosmological models. He believed that astrology is a real science that describes the physical effects of the heavens on terrestrial life. Ptolemy’s most important geographical innovation was to record longitudes and latitudes in degrees for roughly 8,000 locations on his world map. Ptolemy also devised two ways of drawing a grid of lines on a flat map to represent the circles of latitude and longitude on the globe. His grid gives a visual impression of Earth’s spherical surface and also preserves the Proportionality of distances.