Abu Abdallah Muhammad Ibn Jabir Ibn Sinan al-Battanial-Harrani is a great Muslim astronomer mathematician and astrologer. He was of Sabian origin. His name in Latin is Albatenius, Albategnus, or Albategni.

He was born around 858 A.D. in Battan, a State of Harran. Battani received his first education through his father Jabir Ibn San'an al-Battani, who was also a well-known scientist. After this he moved to Raqqa, situated on the bank of the Euphrates, where he received advanced education and later on flourished as a scholar.

He migrated to Samarra at the beginning of the 9th century, and over there he worked till the end of his life in929 A.D.

He is one of the most prominent astronomers in the Islamic history. He contributed in a number of important discoveries in astronomy, which was the result of a long career of 42 years of research beginning at Raqqa when he was young.

His greatest discovery is the remarkably accurate determination of the solar year as being 365 days, 5 hours, 46 minutes and 24 seconds, which is very close to the latest estimates. He found that the longitude of the sun's apogee had increased by 16°, 47' since Ptolemy. This implied the important discovery of the motion of the solar upsides and of a slow variation in the equation of time. He did not believe in the trepidation of the equinoxes, although Copernicus held it.

Al-Battani pointed out with unbelievable accuracy the obliquity of the ecliptic, the length of the seasons and the true and mean orbit of the sun.

He rectified several orbits of the moon and the planets and propounded a new and very ingenious theory to determine the conditions of visibility of the new moon. He proved, in sharp contrast to Ptolemy, the variation of the apparent angular diameter of the sun and the possibility of annular eclipses. Dunthorne used his excellent observations of lunar and solar eclipses in 1749 to determine the secular acceleration of motion of the moon. He also provided very clear solutions by means of orthographic projection for some problems of spherical trigonometry.

In the field of mathematics, he was the first to replace the use of Greek chords by singes, with a clear understanding of their superiority. He also developed the concept of cotangent and furnished their table in degrees.

Abu Abdullah Al Battani wrote a number of books on astronomy and trigonometry. His most famous book was his astronomical treatise with tables, which was translated into Latin in the 12th century and flourished as De scienta stellerum — De numeris stellerum et motibus. An old translation of this is available at the Vatican.

What he wrote on astronomy was extremely influential in Europe till the Renaissance, with translations available in several languages. His original discoveries both in astronomy and trigonometry were of great help in the development of these scientific fields.