c.855 - 929
Al-Battani's great astronomical work 'De motu stellarum' exercised a great influence on European astronomy.
Al-Battani was born in an area which is now in Turkey and lived in Syria, where he carried out astronomical observations.
As a mathematician he found more accurate values for the length of the year, for the annual precession of the equinoxes, and for the inclination of the ecliptic. He also improved the calculation for sinus functions.
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