Ahmad Nahavandi

Ahmad ibn Muhammad al-Nahavandi was a Persian astronomer of the 8th and 9th centuries. His name indicates that he was from Nahavand, a city in Iran.
He lived and worked at the Academy of Gundishapur, in Khuzestan, Iran, at the time of Yahya ibn Khalid ibn Barmak, who died in 803 AD, where he is reported to have been making astronomical observations around the year 800AD. He and Mashallah ibn Athari were among the earliest Islamic era astronomers who flourished during the reign of al-Mansur, the second Abbasid Caliph.
He also compiled tables called the comprehensive (Mushtamil).