Ethiopic Astronomy and Computus

Ethiopic Astronomy and Computus is one of the seminal works of the late Otto Neugebauer. It is still the only detailed work for the English reader on the astronomical/calendar aspect of the Book of Enoch and the calculations of Easter and other movable Christian feasts in the Ethiopian Tewahido Orthodox Church. The material here investigated originates from two different classes of sources: the primitive astronomy of the Book of Enoch on the one hand, and the cleverly arranged Computus of the church calendar on the other. These two groups of sources are separated from each other not only chronologically but also geographically: the Book of Enoch was composed in the last centuries B. C. in the Palestinian area (also represented in the Qumrân archives) while the Computus reflects conditions centuries later within Alexandrian Christianity. from the Introduction