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Arabic Lefends Es-Zerkel

Yet another name must be mentioned, viz., the Spanish-Arab astronomer Ibn Abd-ar-Rahman Es-Zerkel, Europeanized as Arzachal.
He first resided at Toledo, at the court of its sovereign, Mamun, for whom he made an astrolabe, which he called in his honour the Mamunian. He then went to Seville, where he wrote for Motamid bin Abbad (A.D. 1069-1091) a treatise on the use of certain instruments.
During his residence at Toledo he constructed two clepsydras, the waters of which decreased and increased according to the waning and growing of the moon, and these two basins were destroyed only in A.D. 1133 by Alphonse VI., when he took Toledo.

Arzachal left a work on eclipses, and on the revolution of years, as well as the tables of the sky, to which the name of Toledan tables have been given. His writings, but especially the last, which must have been consulted by the editors of the Alphonsine tables, were never translated, and exist only in manuscript in libraries where but few scholars can consult them. Arzachal made many observations in connection with the sun, and was also the inventor of the astronomical instrument called after his name, Zerkalla. He died A.D. 1080.