Claudius Ptolemy by Tihomir Kostadinov GEOG 200B January 14, 2003
Biography Highly uncertain – we don’t know much about his personal life. Highly uncertain – we don’t know much about his personal life. Lived and worked in Alexandria, Egypt. Lived and worked in Alexandria, Egypt. Born ca 85 AD Born ca 85 AD Died ca 165 AD Died ca 165 AD
Biography Greek astronomer, mathematician and geographer. Greek astronomer, mathematician and geographer. Name a mixture of Greek Egyptian “Ptolemy” and Latin “Claudius”. Name a mixture of Greek Egyptian “Ptolemy” and Latin “Claudius”. His teacher was probably Theon of Smyrna, a mathematician. His teacher was probably Theon of Smyrna, a mathematician.
Biography His work was extremely influential and defining fundamental principles for more than a millennium in the Western World. His work was extremely influential and defining fundamental principles for more than a millennium in the Western World. Most influence in astronomy and geography. Most influence in astronomy and geography. Work in astronomy not “refuted” until Nicolaus Copernicus ( ) proposed the heliocentric model, which was actually less precise (without Kepler’s laws)!!! Work in astronomy not “refuted” until Nicolaus Copernicus ( ) proposed the heliocentric model, which was actually less precise (without Kepler’s laws)!!! Work in geography said to have influenced Columbus in his westward explorations. Work in geography said to have influenced Columbus in his westward explorations.
Major works/publications Three major books: Three major books: Almagest (Mathematical Syntaxis) - astronomy, trigonometry, mathematics. Almagest (Mathematical Syntaxis) - astronomy, trigonometry, mathematics. The Geography – maps, geography. The Geography – maps, geography. Tetrabiblos - on astrology. Tetrabiblos - on astrology.
Almagest 13 book treatment on astronomy. 13 book treatment on astronomy. Laid foundations of modern trigonometry. Laid foundations of modern trigonometry. Knew the Earth was a sphere. Knew the Earth was a sphere. Geocentric UNIVERSE view – uses circular motions on several superimposed levels to explain planetary movements. This geocentric view was not improved until Copernicus’s heliocentric model was AUGMENTED with Kepler’s laws!!! Geocentric UNIVERSE view – uses circular motions on several superimposed levels to explain planetary movements. This geocentric view was not improved until Copernicus’s heliocentric model was AUGMENTED with Kepler’s laws!!! 48 constellations (over a thousand stars) catalog with coordinates. Names of constellations still used today. Ecliptic equatorial coordinates used with systematic and other errors. 48 constellations (over a thousand stars) catalog with coordinates. Names of constellations still used today. Ecliptic equatorial coordinates used with systematic and other errors.
Almagest – Geocentric View Used three geometric constructs (eccentric, epicycle, equant) to explain planetary motions, especially the retrograde motion (explained by the epicycles). Used three geometric constructs (eccentric, epicycle, equant) to explain planetary motions, especially the retrograde motion (explained by the epicycles). Classic example of how an empirical model in science can persist and explain phenomena while being inherently WRONG. Classic example of how an empirical model in science can persist and explain phenomena while being inherently WRONG.
The Geography Influential, founding work in geography and cartography. Remained the principal work until the 1500’s. Influential, founding work in geography and cartography. Remained the principal work until the 1500’s. Based on the Earth being a sphere. Based on the Earth being a sphere. His maps are the first known projection of the sphere onto a plane. His maps are the first known projection of the sphere onto a plane.
The Geography Coordinates on maps are degrees of latitude, referenced to the Equator, and degrees of longitude, referenced to some point westward of the most western point. Coordinates on maps are degrees of latitude, referenced to the Equator, and degrees of longitude, referenced to some point westward of the most western point. The work is basically what we call an ATLAS today. Based around the maps. The work is basically what we call an ATLAS today. Based around the maps. Only the index of the maps has remained; the actual maps have disappeared. Only the index of the maps has remained; the actual maps have disappeared. List of places, coordinates, neighboring places, and short descriptions sometimes. List of places, coordinates, neighboring places, and short descriptions sometimes.
References/Sources Used and.ac.uk/~history/Mathematicians/Ptolemy.html and.ac.uk/~history/Mathematicians/Ptolemy.html and.ac.uk/~history/Mathematicians/Ptolemy.html and.ac.uk/~history/Mathematicians/Ptolemy.html Gazetteer/Periods/Roman/.Texts/Ptolemy/home.html Gazetteer/Periods/Roman/.Texts/Ptolemy/home.html Gazetteer/Periods/Roman/.Texts/Ptolemy/home.html Gazetteer/Periods/Roman/.Texts/Ptolemy/home.html emy.html emy.html emy.html emy.html ystem.html ystem.html ystem.html ystem.html Special THANKS to Google, Inc. ( Special THANKS to Google, Inc. (