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Ptolemy Almagest, Book I, 1.

20 In all, Ptolemy tabulated 1022 stars in 48 constellations, giving the longitude, latitude and magnitude of each. He was very interested in the question of whether the stars move in relation to each other and so he gave an extensive list of stars that lay in straight lines so that future observations easily could reveal any relative motion that exists. There is evidence to suggest that Ptolemy took the star catalogue of Hipparchus and added the correction in longitude given by Hipparchus' value for the precession. For the 21 intervening centuries this would amount to 2° 40' which gives a good explanation of why Ptolemy's longitude values are consistently about 1° too small, since, had he used the correct value of the precession, he would have had to add 3° 40'. However, there is no direct evidence that Hipparchus ever produced a systematic catalogue of about 1000 stars as Ptolemy did. More details on this question can be found in Evans (1987) and Shevchenko (1990) and an excellent historical survey of the debate on this question, which has gone on for over 100 years, can be found in Evans (1998); (see also note

solely is to represent the heavenly phenomena by purely kinematic hypotheses. He returned to this question in a later work, the Planetary Hypotheses. However, Ptolemy did use physical arguments to justify his choice of a fixed Earth at the centre of the Universe. He realized that the diurnal rotation of the heavens could equally well be accounted for by a rotating Earth, as espoused by Heraclides, but this was ruled out on the grounds that it would contradict Aristotelian physics.

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