Al-Battani

Al-Battani, Latinized as Albategnius, was an Arab Muslim astronomer, geographer and mathematician of the ninth and early tenth centuries who lived and worked for most of his life at Raqqa, now in Syria. He died in 929. His Kitab az-Zij as-Sabi, written about 900, is the earliest surviving zij, or astronomical table, in the Ptolemaic tradition that is hardly influenced by Hindu or Sasanian astronomy; it refined Ptolemy's Almagest and was translated into Latin in the twelfth century and printed at Nuremberg in 1537. He introduced the use of sines and tangents in geometrical calculations in place of the geometrical methods of the Greeks, and used trigonometry to derive an equation for finding the qibla. His solar observations led him to understand annular solar eclipses, and his values for the solar year and the obliquity of the ecliptic were remarkably accurate.