The talk surveys a unique manuscript made in the fifteenth century CE preserved in the Egyptian National Library which embraces a well-received work by the celebrated Muslim astronomer, al-Farghānī (d. after 861). The manuscript’s last page, however, deals with the monthly division of the daily time according to when the Moon is below or above the Earth. This short, probably incomplete, text which follows by a discussion of the seven climes of the inhabited part of the world, has wrongly been attributed to al-Farghānī by the copyist, leading to further errors in modern catalogues. Through a close look, I found out that this time-keeping treatise is actually part of Kitāb al-Filāḥa al-nabaṭiyya (The Book of Nabatean Agriculture) by Abū Bakr Aḥmad b. Waḥshiyya, written in the early tenth century. By referring to an otherwise unknown Canaanite astronomer, the latter provides a guide to planting times in relation to the moonlight duration in various localities. Despite Ibn Waḥshiyya’s claim of collecting his book form Babylonian elements, recent studies have raised serious doubts about its origin. 

In the talk, the speaker will elaborate more on the characteristics of the manuscript and try to think over this question that under which level of association between advanced and folk astronomical accounts on time-keeping, this textual (con-) fusion happened. She also tries to shed more light on the mathematical knowledge behind the time list to contribute to the curious question of Kitāb al-Filāḥa al-nabaṭiyya’s sources.