alBattani

Al-Battani, whose full name was Abu Abdallah Muhammad ibn Jabir ibn Sinan al-Raqqi al-Harrani al-Sufi al-Amawi, was a prominent Arab astronomer and mathematician of the late 9th and early 10th centuries. He was born in Harran, Mesopotamia, in 858 AD and died in 929 AD. Al-Battani made significant contributions to astronomy, refining astronomical tables and improving measurements of celestial phenomena.

His most influential work is the Kitab al-Zij, also known as De scientia stellarum (On the Science of the Stars). In this book, he presented his astronomical observations and calculations, which were highly accurate for his time. Al-Battani meticulously recorded the positions and motions of the sun, moon, and planets. He is credited with determining the length of the solar year with remarkable precision, estimating it to be 365 days, 5 hours, 46 minutes, and 24 seconds. He also accurately calculated the precession of the equinoxes and the inclination of the Earth's axis.

Al-Battani's work had a profound impact on both Islamic and European astronomy. His data and methods were incorporated into later astronomical tables and were used by European scholars such as Copernicus and Kepler. He introduced and popularized the use of trigonometric functions in astronomy and provided tables for them, including the sine and tangent. His work advanced the understanding of astronomical cycles and celestial mechanics, solidifying his reputation as one of the most important astronomers of the Middle Ages.