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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.
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.
Notable features of Ptolemy's map is the first use of longitudinal and latitudinal lines as well as specifying terrestrial locations by celestial observations. The Geography was translated from Greek into Arabic in the 9th century and played a role in the work of al-Khwārizmī before lapsing into obscurity. The idea of a global coordinate ...
Nederlands: The Ptolemaic system is an ancient astronomical model that posits the Earth as the center of the universe, with the planets, the Sun, and the stars orbiting around it in a series of concentric circles.
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The term might be used, for example, to describe continuing to try to adjust a theory to make its predictions match the facts. There is a generally accepted idea that extra epicycles were invented to alleviate the growing errors that the Ptolemaic system noted as measurements became more accurate, particularly for Mars.
America began to appear in maps as early as 1500, with the world map of Juan de la Cosa, in 1502, with the Cantino planisphere, and in 1507, with Waldseemüller map, the fisrt to use the name "America". During the 16th century, the Americas were shown in dozens of maps, with increasing detail and accuracy.
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