Abū Ishāq Ibrāhīm al-Zarqālī

Az- Zarqali, Abu Ishaq Ibrahim ibn Yahya completely on - Naqqasch az- Zarqali (Arabic أبو إسحاق إبراهيم بن يحيى النقاش الزرقالي, DMG Abu Ishaq Ibrahim bin Yahya az - Naqqāš - Zarqālī; often than Naqqash - or - naqqash or as al - Zarqali transcribed ), the latin -speaking Europe Arzachel and in Spanish and Italian Azarquiel (* 1029 in Toledo, † 1087 in Seville), was a leading Arab mathematician and the most outstanding astronomer of his time.

He worked in Toledo, which flourished under the Moors as Tolaitola, and during the Caliphate of Cordoba and the capital of the Taifa of Dhun - Nuniden until the Christian conquest by Alfonso VI. on May 25, 1085th After this Reconquista az- Zarqali emigrated to Seville, where he died.

Az- Zarqali combined theoretical knowledge with technical skill and created astronomical precision instruments. He designed, among other things, a flat astrolabe that could be used at any latitude, and could indicate a water meter, the day and night hours, and the day of the lunar month.

He was able to correct the geographic data of Ptolemy, in particular the expansion of the Mediterranean. az- Zarqali could also be the first on the Earth's orbit (?) show the motion of the apse (the two main vertices of an approximately elliptical orbit of a planet ) relative to the underlying fixed stars with numbers. His calculation of the exact value of Apsidendrehung came remarkably close to today.

Az- Zarqali also contributed significantly to the well-known Toledans panels, a compilation of astronomical data hitherto unprecedented accuracy. Even his own " Almanac " was very well known and were thus able to determine the date on which the Coptic, Roman, Persian, or "real" lunar month begins. Especially for the later emergence of deep-sea shipping its tables were used to predict solar and Mondekliptik and to calculate the latitude and longitude of great importance.

The work az- Zarqalis was the translation of Gerard of Cremona (1114-1187), who came to Toledo, translated into Latin and so famous throughout Europe. This contributed significantly to the revival of scientific, based on mathematics, astronomy in the Christian West of the 12th century. Due to the many different languages ​​( high level languages ​​like Modern Standard Arabic, Hebrew, Latin and vernacular languages ​​such as Arabic - Andalusian, Romanesque - Castilian) was Toledo in the 12th and 13th centuries an important center for the translation of Arabic writings into Latin and Romance. Even four centuries later emphasized Nicolaus Copernicus, how much he owed AZ- Zarqali for his work and quoted him in the seminal work De revolutionibus Orbium Coelestium.

After az- Zarqali the crater Arzachel was named on the moon, the moon is close to the center and a diameter of 96 km has - see list of lunar craters.

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