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For the Moon, Ptolemy began with Hipparchus' epicycle-on-deferent, then added a device that historians of astronomy refer to as a "crank mechanism": [28] he succeeded in creating models for the other planets, where Hipparchus had failed, by introducing a third device called the equant. Ptolemy wrote the Syntaxis as a textbook of mathematical ...
Opening chapter of the first printed edition of Ptolemy's Tetrabiblos, transcribed into Greek and Latin by Joachim Camerarius (Nuremberg, 1535).. The commonly known Greek and Latin titles (Tetrabiblos and Quadripartitum respectively), meaning 'four books', are traditional nicknames [24] for a work which in some Greek manuscripts is entitled Μαθηματικὴ τετράβιβλος ...
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 ...
Ptolemy did not predict the relative sizes of the planetary deferents in the Almagest. All of his calculations were done with respect to a normalized deferent, considering a single case at a time. This is not to say that he believed the planets were all equidistant, but he had no basis on which to measure distances, except for the Moon.
In Almagest V, 11, Ptolemy writes: . Now Hipparchus made such an examination principally from the sun. Since from other properties of the sun and moon (of which a study will be made below) it follows that if the distance of one of the two luminaries is given, the distance of the other is also given, he tries by conjecturing the distance of the sun to demonstrate the distance of the moon.
Originating from the Thebaid region of Upper Egypt, he worked at Alexandria and wrote works on astronomy including the Almagest, the Planetary Hypotheses, and the Tetrabiblos, as well as the Handy Tables, the Canobic Inscription, and other works unrelated to astronomy. Ptolemy's Almagest (originally titled The Mathematical Syntaxis) is one of ...
Ptolemy's Handy Tables (Ancient Greek: πρόχειροι κανόνες, romanized: Procheiroi kanones) is a collection of astronomical tables that second century astronomer Ptolemy created after finishing the Almagest. The Handy Tables elaborated the astronomical tables of the Almagest and included usage instructions, but left out the ...
The Canon of Kings was a dated list of kings used by ancient astronomers as a convenient means to date astronomical phenomena, such as eclipses.For a period, the Canon was preserved by the astronomer Claudius Ptolemy, and is thus known sometimes as Ptolemy's Canon.