First scientific measurements of time The first known definite scientific measurements of time in astronomical observations made with the help of a mechanical clock were by Bernhard Walther in 1484. Walther (b. 1430, d. 1504) was a merchant of modest means in Nuremberg. His knowledge of Greek gave him access to humanists circles in the city. This is where he met Johannes Müller von Königsberg (b. 1436, d. 1476), better known as Regiomontanus, a German mathematician, astrologer and astronomer active in Vienna, Buda and Nuremberg. The two made astronomical observations together. In 1475, Regiomontanus was summoned to Rome assist the Vatican in reforming the calendar. After Regiomontanus’ death in 1476, Walther became responsible for observing and collecting these data, which he did for the next 30 years, until 1504, just before his own death. It is clear that he also used a zodiacal armillary sphere (similar to Ptolemy’s armillary sphere) to measure some of the planetary positions. Although Walther’s observations were quite accurate, they exposed the limitations of the zodiacal armillary sphere. His observations were printed for the first time in 1544. You can read about them in Richard L. Kremer’s article ‘Bernard Walther’s astronomical observations’. Further Reading Kremer, R. L. 1980. ‘Bernard Walther’s astronomical observations’ in Jounral for the History of Astronomy 2: 174–191. Matthes, D. and R. Sánchez-Barrios. September 2017. ‘Mechanical clocks and the advent of scientific astronomy’ in Antiquarian Horology 38(3): 328–342 (see especially pp. 330–333). Image Credit Master of the Housebook (active c1470-1500) - 1482 (circa), Das Mittelalterliche Hausbuch, edd. Helmuth Th. Bossert and Willy F. Storck, Leipzig 1912, pl. 16. © The Warburg Institute, School of Advanced Study, University of London, CC BY-NC 3.0, https://iconographic.warburg.sas.ac.uk/object-wpc-wid-ddxp
