Claudius Ptolemy: Astronomy and Cosmography

Ptolemy’s astronomical treatise Almagest, written in Alexandria in the 2nd century, was first published in Venice, in a Latin translation, in 1515. By then there were already some dozen editions of his Geographia, more commonly given the title Cosmographia in the 16th century. The discipline of ‘cosmography’ dealt with the whole cosmos: the heavens and the earth and the relationship between them. Maps, globes, spheres and sundials were all tools of cosmographical work.

Cosmography had an astronomical component, dealing with the stars, the sun and their motions. The imaginary circles astronomers traced in the heavens – such as the celestial equator and the topics of Cancer and Capricorn – had their equivalents on earth, and the appearance of the starry heavens depended on the observer’s location on earth. All of this fell within astronomical cosmography; only the specialist mathematical astronomers had to deal with the more challenging motions of the planets other than the sun and to read Almagest.

Featured objects

1. Claudius Ptolemy,Almagest (Venice, 1515)
14. Peter Apian, Astronomicum Caesareum (Ingolstadt, 1540)
21. Altitude sundial and horary quadrant by Miniato Pitti, Florence, 1558
25. Horary quadrant and altitude sundial by Christian Heiden, German, 1553


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