Treatise for Observers on Constructing the Circle of Projection
This work is a treatise on the important subject of timekeeping. It is a work of technical astronomy, in 19 folios, that begins by emphasizing the religious significance of knowledge of time. It is divided into an introduction, two chapters, and a conclusion. Comprehensive procedures for the construction of tables and their use are provided. The work was completed in 1473 (878 A.H.).