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Counting the total number is difficult, but estimates are that he created a system just as complicated, or even more so. [16] Koestler, in his history of man's vision of the universe, equates the number of epicycles used by Copernicus at 48. [17] The popular total of about 80 circles for the Ptolemaic system seems to have appeared in 1898.
In graph theory, a Ptolemaic graph is an undirected graph whose shortest path distances obey Ptolemy's inequality, which in turn was named after the Greek astronomer and mathematician Ptolemy. The Ptolemaic graphs are exactly the graphs that are both chordal and distance-hereditary ; they include the block graphs [ 1 ] and are a subclass of the ...
Pages from 1550 Annotazione on Sacrobosco's De sphaera mundi, showing the Ptolemaic system. In the Ptolemaic system, each planet is moved by a system of two spheres: one called its deferent; the other, its epicycle. The deferent is a circle whose center point, called the eccentric and marked in the diagram with an X, is distant from the Earth.
Latitude was expressed in degrees of arc from the equator, the same system that is used now, though Ptolemy used fractions of a degree rather than minutes of arc. [24] His Prime Meridian , of 0 longitude , ran through the Fortunate Isles , the westernmost land recorded, [ 25 ] at around the position of El Hierro in the Canary Islands . [ 26 ]
A simple illustration showing the basic elements of Ptolemaic astronomy. It shows a planet rotating on an epicycle which is itself rotating around a deferent inside a crystalline sphere. The center of the system is marked with an X, and the earth is slightly off of the center.
The basic elements of Ptolemaic astronomy, showing a planet on an epicycle (smaller dashed circle), a deferent (larger dashed circle), the eccentric (×) and an equant (•). Equant (or punctum aequans) is a mathematical concept developed by Claudius Ptolemy in the 2nd century AD to account for the observed motion of the planets. The equant is ...
There is a famous (but probably apocryphal) [7] quote attributed to Alfonso upon hearing an explanation of the extremely complicated mathematics required to demonstrate Ptolemy's geocentric model of the solar system: "If the Lord Almighty had consulted me before embarking on creation thus, I should have recommended something simpler.")
Download as PDF; Printable version; ... move to sidebar hide. Ptolemaic is the adjective formed from the name Ptolemy, and may refer to: ... Ptolemaic system, ...