The computation of planetary longitudes in the zij of Ibn al-Banna' [Ressource électronique] / Julio Samso and Eduardo Millas

Notes bibliogr.

Ibn al-Bannā' of Marrakesh (1256-1321) is the author of one of the four extant "editions" of the unfinished zīj of Ibn Isḥāq (fl. Tunis and Marrakesh ca. 1193-1222): it contains a selection of his tables accompanied by a collection of canons, easy to understand, which makes the zīj accessible for the computation of planetary longitudes. The present paper studies some modifications of the structure of the tables the purpose of which is to make calculations easier. The tables of the planetary and lunar equations of the centre are "displaced." The tables of the equation of the anomaly of Mars, Venus and Mercury, are standard, while, in the cases of Jupiter and Saturn, the equation of the anomaly is calculated in the same way as that for the Moon. Ibn al-Bannā' appears as a clever adapter, who displays a clear ingenuity allowing him to introduce formal modifications which give his work an appearance of novelty which does not correspond to reality