This paper surveys the results established so far by the on-going research on the planetary theories in Arabic astronomy. The most important results of the Maragha astronomers are gathered here for the first time, and new areas for future research are delineated. The conclusions reached demonstrate that the Arabic astronomical works mentioned here not only elaborate the connection between Arabic astronomy and Copernicus, but also that such activities, namely the continuous reformulation of Greek astronomy, were not limited to a specific (...) group of astronomers or to a specific geographical area. It is shown that such activities were spread over a period of more than seven hundred years, from the early eleventh till the sixteenth century, and over an area stretching from the Andalusian peninsula in the west to the farthest reaches of Central Asia in the east. L'auteur expose, dans cet article, les résultats établis jusqu'ici par les recherches en cours concernant les théories planétaires de l'astronomie arabe. Les résultats les plus importants relatifs aux astronomes de Maragha sont rassemblés ici pour la première fois et le contour de nouveaux domaines pour la recherche future s'y trouve délimité. Les conclusions auxquelles on parvient dans cet article montrent d'une part que les oeuvres en astronomie mentionnées nous permettent de mieux saisir la liaison entre l'astronomie arabe et celle de Copernic, d'autre part que l'activité de reformulation continue de l'astronomie grecque ne fut limitée ni à un groupe spécifique d'astronomes, ni à une aire géographique déterminée. On montre ici qu'une telle activité s'est en fait étendue sur une période de plus de sept siécles, depuis le début du Xle siècle jusqu'au XVIe siècle, et sur une aire allant de la péninsule andalouse à l'Ouest jusqu'aux confins les plus éloignés de l'Asie centrale à l'Est. (shrink)

This paper surveys the results established so far by the on-going research on the planetary theories in Arabic astronomy. The most important results of the Maragha astronomers are gathered here for the first time, and new areas for future research are delineated. The conclusions reached demonstrate that the Arabic astronomical works mentioned here not only elaborate the connection between Arabic astronomy and Copernicus, but also that such activities, namely the continuous reformulation of Greek astronomy, were not limited to a specific (...) group of astronomers or to a specific geographical area. It is shown that such activities were spread over a period of more than seven hundred years, from the early eleventh till the sixteenth century, and over an area stretching from the Andalusian peninsula in the west to the farthest reaches of Central Asia in the east. (shrink)

This paper presents an analysis of the systematic astronomical observations performed by Muḥyī al-Dīn al-Maghribī at the Maragha observatory between 1262 and 1274 AD. In a treatise entitled Talkhīṣ al-majisṭī, preserved in a unique copy at Leiden, Universiteitsbibliotheek, Muḥyī al-Dīn explains his observations and measurements of the Sun, the Moon, the superior planets, and eight reference stars. His measurements of the meridian altitudes of the Sun, the superior planets, and the eight bright stars were made using the mural quadrant of (...) the observatory, and the times of their meridian transit using a water clock. The mean absolute error in the meridian altitudes of the Sun is ~ 3.1′, of the superior planets ~ 4.6′, and of the eight fixed stars ~ 6.2′. The clepsydras used by Muḥyī al-Dīn could apparently fix time intervals with a precision of ± 5 min. His estimation of the magnitudes of three lunar eclipses observed in Maragha in 1262, 1270, and 1274 AD is in close agreement with modern data. (shrink)