Mit Sphaera und Astrolab

This book offers a study of the scientific landscape of medieval Bavaria during the higher Middle Ages. Based on manuscripts as well as medieval library catalogues, it tries to quantify the so-called ‘Discovery of Nature’ and tries to analyse it from the perspective of a monastic landscape in which the arrival of the astrolab in the 11th century marked a significant turning point. By introducing new methods and questions into the traditional body of Carolingian astronomy, monastic scholars of this area played a decisive, albeit neglected, role in the development of medieval astronomy.

The book reconstructs the studies of the monk Wilhelm von Hirsau who tackled some of the most urgent problems of astronomy of his time: correcting the dates of the solstices and finding latitude. These studies are then placed in the broader development of medieval science, particularly focusing on his sphaera, an instrument that has often been wrongly understood as a teaching device. In contrast, the present study argues that this instrument is not only William’s lost astronomical clock, but also the first example for stationary observational astronomy in medieval Europe as well as an important milestone towards the empirical astronomy of future centuries.