The Astronomical Clock of Strasbourg Cathedral

Function and Significance


Strasbourg Cathedral’s astronomical clock is one of the most famous monuments to Time in the world. No other clock has been described and appreciated so often and in such a myriad of ways. There were three clocks built consecutively within the cathedral: the earlier fourteenth century clock has left little trace; a second clock was realized in 1570-1574; while the nineteenth century clock began as a proposal for repairs, but was intended by its maker as a replacement clock. This book gives a detailed outline of the artistic and technical components of the second clock, much of which survives, and it describes the astronomical indications and its underlying conceptual framework. The author has discovered a hitherto disregarded contemporary statement that the clock displays four ways of determining the ascendant as described by Ptolemy. He also shows that the Strasbourg clock is the result of a highly original reception of the architectural theory of Vitruvius and other mathematical and mechanical texts of Late Antiquity.

Revised and updated translation from the German edition Die Straßburger Münsteruhr: Funktion und Bedeutung eines Kosmos-Modells des 16. Jahrhunderts. Published by GNT-Verlag in 1993.

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Günther Oestmann, Ph.D. (1992), Technical University Berlin, is a professional clockmaker and Professor for History of Science. His fields of research are the history of scientific instruments and clocks, history of astronomy and mathematical geography, as well as maritime history.
"[The author] penetrative account is technically and historically fascinating, richly referenced, amply illustrated and indispensible to the many who fall under Strasbourg’s spell." - Sebastian Whitestone, Antiquarian Horology, September 2020, pp. 411-413.
 List of Illustrations
 List of Abbreviations


Part 1: The First Clock in the Strasbourg Cathedral and the Project for a New Clock in the Sixteenth Century

1 The First Clock in the Strasbourg Cathedral
 1.1 The Automata of the First Cathedral Clock

2 The Clock on the Tower Platform

3 The Project for Building a New Clock in the First Half of the Sixteenth Century

4 Completion of the Second Clock in 1571–1574
 4.1 Conrad Dasypodius
 4.2 Isaac and Josias Habrecht
 4.3 Tobias Stimmer
 4.4 The Commission of 1571 and the Completion of the Second Cathedral Clock

Part 2: The Artistic Embellishments of the Second Clock

5 The Artistic Decoration of the Clock Housing
 5.1 Pictorial Representations of the Clock
 5.2 General Description of the Clock Housing
 5.3 The Lowest Tier
 5.4 The Central Clock Tower
 5.5 The Tower for the Weights

6 The Portrait of Copernicus: Did Conrad Dasypodius Adhere to Heliocentrism?

Part 3: The Technical Components of the Clock

7 Gear Trains and Layout
 7.1 Principal Arrangement
 7.2 The Clockwork
 7.3 Gear Train for the Mechanical Cock and Carillon
 7.4 Transmissions

8 The Celestial Globe
 8.1 The Sphere of Archimedes
 8.2 Gear Train of the Celestial Globe

9 The Astrolabe Dial
 9.1 Layout of the Tympanum
 9.2 Ecliptic Ring and Hands for Planets
 9.3 Gear Train for the Astrolabe

10 Calendar Disk and Sundials
 10.1 The Calendar Disk
 10.2 The Sundials on the Gable of the Cathedral’s Southern Transept

Part 4: Programmatic Meanings

11 Clock Construction and Architectural Theory
 11.1 Dasypodius’s Reception of Vitruvius
 11.2 The Emblematic Painting on the Weight Drive Tower
 11.3 The ‘Late Gothic’ Architecture of the Clock Housing

12 Influences of Alexandrine Technology

13 The ‘Inventio Prima’ of Dasypodius
 13.1 Claudius Ptolemy’s Tetrabiblos
 13.2 Dasypodius’s Commentary to Ptolemy’s Tetrabiblos

 Appendix 1: Dasypodius’s Commentary on Chapter 2 of Book III of Ptolemy’s Tetrabiblos
 Appendix 2: The Lost Astronomical Clock of 1583
 Appendix 3: Excerpt from the Protheoria mathematica by Conrad Dasypodius, 1593
 Appendix 4: Excerpt from a Letter by Paul Virdung to Kepler, 1604
 Appendix 5: The Divisions of Mathematics according to Geminos
Sources and Bibliography
 A. Manuscripts
 B. Printed Sources and Secondary Literature
All interested in the history of horology, astronomy, technological and cultural history of the Early Modern Period.