Chapter Nine. Celestial Maps And Illustrations In Arabic-Islamic Astronomy

Abstract

Maps of the entire sky are unknown in the Islamic world, although the possibility of mapping the celestial sphere on a plane surface is well attested in theory. In Arabic-Islamic astronomy, maps of the entire sky exist only on celestial globes and, in an abstract form, on the retes of astrolabes. The astrolabe is a two-dimensional representation of the phenomena appearing in three dimensions. Arab cartographers knew the details of Ptolemy ?s constellations through the Greek celestial globes. Arabic-Islamic astronomers usually included in their writings either the complete catalogue of 1,025 stars, arranged in 48 constellations in the Ptolemaic tradition, or shorter tables of the most significant major stars for use on instruments. Their geometrical diagrams illustrate calculation procedures to solve questions in theoretical astronomy. They often include diagrams on cosmological phenomena, such as eclipses and the arrangement of the celestial bodies in the classical geocentric system. Keywords: Arabic-Islamic astronomy; celestial sphere; geometrical diagrams; maps; Ptolemaic tradition