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Muhammad Ibn Jabir Al-Harrani Al-Battani (850 AD–923 AD) was nicknamed as Albatenius. He was a famous Muslim astronomer, astrologer and mathematician. He invented a number of trigonometric relations. His greatest achievement was to determine the solar year. He found out that it has 365 days, 5 hours, 46 minutes and 24 seconds. The new tables of the sun and the moon were complied by him. He discovered the direction of the sun's apogee.
He independently introduced the use of sines in calculation and put a partial effort on the tangents.  He had also been successful in calculating the values of equinoxes and the obliquity of the elliptic. Copernicus, Kepler and Galileo mentioned him in their works. Kitab az Zij is his most important work. This work put emphasis on Ptolemy's Theory. In this book, he gave the description of a quadrant instrument or the observation tube. His work has been translated in both Spanish and Latin. The moon crater Albatenius was named after him.