Arzachel, Abraham

, or Eizarakel, a native of Toledo, in the twelfth century, was one of the most celebrated astronomers who appeared after the time of the Greeks, and before the revival of learning. He wrote a treatise on the “obliquity of the Zodiac,” which he fixed, for his time, at 23 34', and determined the apogee of the sun by four hundred and two observations. The famous Alphonsine Tables, published by order of Alphonsus, king of Castille, were partly taken from the works of Arzachel. Few particulars are known of the personal history of this | astronomer, unless that he was of the Jewish persuasion. Montucla says that his tables are preserved in several libraries, in manuscript, with an introduction which explains their use. ¹