Habash al-Hasib (häbäshˈ äl-häsēbˈ) [key], d. c.870, Arab mathematician and astronomer. Habash al-Hasib was born in what is now Mary, Turkmenistan, and worked in Baghdad. He calculated tables of sines, tangents, and standard astronomical functions. He found formulas for calculating the positions and orbits of celestial bodies that go beyond the Ptolemaic theory on which they are based.
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