مشخصات پژوهش

This paper presents an analysis of the systematic astronomical observations performed by Muh. y¯ı al-D¯ın al-Maghrib¯ı (d. 1283 AD) at theMaragha observatory (northwestern Iran, ca. 1260–1320 AD) between 1262 and 1274 AD. In a treatise entitled Talkh¯ıs. al-majist.¯ı (Compendium of the Almagest), preserved in a unique copy at Leiden, Universiteitsbibliotheek (Or. 110), Muh. y¯ı al-D¯ın 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 Muh. y¯ı al-D¯ın 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.