A Twelfth-Century Astronomical Textbook: Cambridge, Fitzwilliam Museum, MS McClean 165 and its Pedagogical Value and Evidence

The twelfth century saw an increase in the number of astronomical works as European scholars strove to understand the design of the universe. Both mathematical treatises and manuals of observation circulated with surprising speed. Yet, for all of this interest and writing, there was no single work that related the whole discipline to eager students. Aspiring scholars required several works in order to learn and practice astronomy. They needed primers for a basic grasp of terminology and theory, mathematical textbooks, guidebooks for instruments like the astrolabe, and a method for recording observations for computation. While historians study the circulation of an astronomical work, they often do not consider which works were bound together and how that combination might produce a serviceable understanding of this discipline. In order to determine how twelfth-century Europeans learned astronomy, it is crucial to analyze original manuscripts for their pedagogical value.

Many twelfth-century codices contain works on astronomy, but there are rare occasions when all the necessary instructive elements appear in one manuscript. Cambridge, Fitzwilliam Museum, MS McClean 165 is a manuscript which could have served as a compendium of astronomical knowledge. It contains rudimentary lists of planets and their movements, but it also provides experts with a manual for the astrolabe and methods for computing astronomical tables. This manuscript also offers an assortment of astronomical traditions with standard works from late antique authors along with others newly translated from Arabic. The range of instruction and traditions in MS McClean 165 alludes to its possible value as a textbook, yet its marginal notes indicate that someone not only used this manuscript, but also learned and applied the methods advocated in it. MS McClean 165 is an excellent representative of a medieval astronomical textbook and of a pre-Enlightenment movement in astronomy toward a science which mixed observation and computation.