Walcher of Malvern
Walcher was from Lotharingia and arrived in England around 1091. Using an astrolabe to measure the time of several solar and lunar eclipses with an accuracy of about fifteen minutes for his early observations, he computed a set of tables giving the time of the new moons from 1036 through 1111, which were considered important for medical astrology. His later observations revealed significant errors in his tables, reflecting the limitations of early medieval astronomical theory.
In one of his later writings, which drew on Arabic astrology-astronomy received from Spain, he recorded angles in degrees, minutes, and seconds, although he wrote these numbers using Roman, rather than Arabic numerals.
Walcher was Prior of Malvern Priory from 1120 to 1135. Walcher's gravestone in St Anne's Chapel at the Priory Church records his abilities:
"Philosophus bonus dignus Astrologus lotharingus, Vir pius et humilis, Monachus prior hujus ovilis Hic jacet in cista Geometricus et Abacista, Doctor Walcherus. Flet plebs, dolet undique clerus. Huic lux prima mori Dedit Octobris seniori; Vivat ut in coelis Exoret quisque fidelis. MCXXXV."
"A good philosopher, a worthy Astrologer of Lorraine, A pious and humble man, the prior monk of this fold, Here lies in a casket, a geometer skilled in the abacus, Doctor Walcher. The people weeps, the cleric grieves everywhere. To him, our elder, the first day of October brought death; That he should live in heaven may every faithful soul pray. 1135."
- C. H. Haskins, Studies in the History of Mediaeval Science, (Cambridge: Harvard Univ. Pr., 1927), pp. 112-117
- S. C. McCluskey, Astromomies and Cultures in Early Medieval Europe, (Cambridge: Cambridge Univ. Pr., 1998), pp. 180-184.
- Great Malvern Priory: Prior Walcher of Lorraine Retrieved 22 September 2011