The Computation of Planetary Longitudes in the Zij of Ibn Al-Bannā'

The Minhaj al-talib fi ta’dll al-kawakib of Ibn al-Banna’ al-Marrakushi is a zij the interest of which lies more in the changes introduced by its author in the techniques of computation of planetary longitudes than in its contents. The latter derive basically from the set of tables prepared by Abu al’ Abbas ibn Ishaq al-Tamirm al-Tunisi, which survive in a unique manuscript in Hyderabad, discovered in 1978 by D.A. King. The tables of Ibn Ishaq appear to derive essentially from the Toledan astronomer Ibn al-Zarqalluh and they were probably an unfinished work not accompanied originally by an elaborate collection of canons.