The exact date of his birth is not known, scientists name 798. Full name of the scientist is Abu al-Abbas Ahmad ibn Muhammad ibn Kathir al-Fargani. A native of the Fergana Valley was respectfully called Hasib, which means “mathematician”, and in Europe he was known as Alfraganus.
He made his contribution to astronomy, mathematics and geography while working in the “House of Wisdom” or the Academy of Al-Mamun (Baghdad). Among his major works there are “The Book of astronomic Movements and Summary of the Science of the Stars”, “Thirty Elements”, “Theoretical calculations on the sphere”, “Treatise on the time, when the moon is under the ground and above it” and others. Ahmad al-Ferghani has also written comments on the work “Almagest” of Ptolemy.
Al Ferghani is one of the first scholars of the Middle Ages who proved sphericity of the Earth, detected the presence of spots on the sun, identified the June 22 as the longest day of the year and 23 December as the shortest. The works of Al-Ferghani were used as a teaching tool for a few centuries in Europe.
Works of Al Ferghani are valued in the scientific world to this day. For example, his invention called nilometer – a device which measures the water level in the Nile – is still used today.