Papers by Günther Oestmann
Strasbourg Cathedral’s astronomical clock is one of the most famous monuments to Time in the worl... more Strasbourg Cathedral’s astronomical clock is one of the most famous monuments to Time in the world. In the thesis an outline of the artistic and technical components of the second clock of 1571-74, is astronomical indications and its underlying conceptual framework is presented. This includes a previously unnoticed contemporary source that proves that the clock shows four ways of determining the ascendant, as described by Ptolemy.
![Research paper thumbnail of „Astronomical Clocks in the Baltic Sea Region“, in: BRENTJES, Rana, Sonja BRENTJES und Stamatina MASTORAKOU (eds.), Imagining the Heavens across Eurasia from Antiquity to Early Modernity, s. l. [Sesto San Giovanni] 2024, 313–329](https://a.academia-assets.com/images/blank-paper.jpg)
From the middle of the fourteenth century until the Early Modern period several monumental astron... more From the middle of the fourteenth century until the Early Modern period several monumental astronomical clocks were erected in Europe, and on many of them astrolabe dials were placed. The coast of the Baltic Sea is a special ‘clock region’, insofar as several monumental astronomical clocks can still be found in the Hanseatic cities of Lübeck, Wismar, Rostock, Stralsund and Danzig, as well as in the Monastery of Doberan and Lund’s Cathedral. These clocks have distinctive features, and all (with the exception of those in Rostock and Danzig) display astrolabe dials with a rather unusual stereographic projection from the North Pole contrary to a projection from the South Pole, which is commonly used on portable astrolabes. This chapter gives an overview of individual astronomical clocks in the Baltic coast region, and a short survey of the function and significance of astronomical clocks in church buildings.
In 1619 the Harmonices mundi libri V was published, which Kepler considered his greatest work. It... more In 1619 the Harmonices mundi libri V was published, which Kepler considered his greatest work. It is well-known and famous for containing the Third Law of Planetary Motion, but book IV deals with his attempt to reform astrology within a Pythagorean-Platonic framework, and here he presented a new understanding of the mechanism of the aspects. Kepler's "astrology of resonance" had repercussions among contemporary astrologers in the 17th century, such as Christopher Heydon, Abdias Trew and Peter Crüger. His ideas of a physical basis for celestial motions and were viewed critically however, and in the perspective of the Age of Enlightenment Kepler's speculative approaches, as well as his metaphysical and religious arguments met with skepticism and disapproval. The tide turned in the Romantic Era, when just these aspects came to the fore and paved the way to an edition of Kepler's works. The German philosophers F. W. J. Schelling (1775-1854), E. F. Apelt (1812-1859) and the astronomer J. W. A. Pfaff (1774-1835) played a crucial role in the rediscovery and reappraisal of Kepler. Pfaff worked on a German translation of the Harmonices mundi, and the teacher of mathematics Christian Frisch (1807-1881), who had studied under Pfaff in Erlangen, published the first critical edition of Kepler's works from 1858 to 1871.
Between 1650 and 1664, a giant globe was created in Gottorf under Duke Friedrich III, which was w... more Between 1650 and 1664, a giant globe was created in Gottorf under Duke Friedrich III, which was widely known and marvelled at by many contemporaries as a wonder of the world. The scientific management of the project was the responsibility of the court mathematician and librarian Adam Olearius. The Gottorf Globe and its counterpart (a “Sphaera Copernicana”) presented the astronomical knowledge of the time in a pictorial form. The image of the earth and the cosmos was also intended to show the Creator and his omnipotence. Erhard Weigel, professor of mathematics at the University of Jena from 1653, also constructed monumental globes. These baroque world models, as well as Robert Long’s 18th-century sphere, can be considered the precursors of today’s planetariums.
https://biblioscout.net/journal/stl/54/1
Die in den Jahren 1571–74 von den Gebrüdern Habrecht gebaute astronomische Uhr im Straßburger Mün... more Die in den Jahren 1571–74 von den Gebrüdern Habrecht gebaute astronomische Uhr im Straßburger Münster ist das wohl bekannteste Exemplar ihrer Gattung überhaupt. Der Aufsatz behandelt das komplexe, von dem Mathematiker Conrad Dasypodius formulierte Bild- und Anzeigenprogramm, das jener in zwei deutschen Beschreibungen und einem lateinischen Traktat der Nachwelt überliefert hat. Den „Generalschlüssel“ zur Deutung der Uhr als „Altar der Astrologie“ hat er jedoch in einem Kommentar zur „Tetrabiblos“ des Claudius Ptolemäus versteckt.
In the early modern period, a profound change in natural science was in the offing, and the publi... more In the early modern period, a profound change in natural science was in the offing, and the publication of William Gilbert's book De Magnete in 1600 marked a crucial year. One of the first to recognise the historical importance of natural science and its role in the life of humanity was the English Lord Chancellor Francis Bacon. He established a general methodology of science and described its possible applications.
Review Heilen, Stephan. Konjunktionsprognostik in der Frühen Neuzeit, vol. I (= Saecula Spiritalia, 53). Baden-Baden 2020, in: DICK, Wolfgang R. und Jürgen HAMEL (Hg.), Beiträge zur Astronomiegeschichte, 15 (= Acta Historica Astronomiae, 69), Leipzig 2022, S. 479–480
In addition to the biobibliographical information on J. W. A. Pfaff available to date, two hither... more In addition to the biobibliographical information on J. W. A. Pfaff available to date, two hitherto little-known sources are presented, one of which is available in printed form. The other is kept in the Municipal Archive of Erlangen.
In the 16th and early 17th centuries, astrology still held a respectable position, though not wit... more In the 16th and early 17th centuries, astrology still held a respectable position, though not without controversy. Johannes Kepler was involved with astrology throughout his life, and his statement about the “highly reasonable astronomia”, whose livelihood had to be provided by astrology as her “foolish daughter”, is often quoted. However, it would be wrong to conclude from this that he rejected astrology, for Kepler’s attitude to it was complex and has often been misinterpreted.
This is an expanded version, with references, of a lecture given by the author on 27 October 2021 in the “Runtingerhaus” in Regensburg.
In addition to rolling ball clocks, the cross-beat designed by Jost Bürgi (1552–1632) was an impo... more In addition to rolling ball clocks, the cross-beat designed by Jost Bürgi (1552–1632) was an important step towards precise timekeeping. Clocks equipped with this escapement are very rare. The finely crafted and previously unpublished cross-beat clock in the form of a monstrance by Caspar II Buschmann (b. c. 1536, †1613) described below came up for auction at Antiquorum in Geneva on 14 November 2004 and at Sotheby's on 3 July 2019. The present owner kindly allowed the author to examine this extraordinary rarity in detail. It is one of the most important clocks of the early modern period and is also an important example of the reception of Bürgi’s escapement construction.
Monumental astronomical clocks display time in varied ways – i.e. with multiform visual features,... more Monumental astronomical clocks display time in varied ways – i.e. with multiform visual features, sound contrivances, and automata – and telling time was just one, and not even the most relevant, of their purposes. What did such an intricate mechanical device mean to the contemporary spectator? This paper aims at a comprehensive interpretation of astronomical clocks, which were the most advanced and complicated mechanisms of their time. Theoretical issues involved in their construction and composition shall be examined, with special consideration of the astronomical clock of Strasbourg Cathedral.
The article covers the execution of a pendulum clock according to the construction of H. J. Kesse... more The article covers the execution of a pendulum clock according to the construction of H. J. Kessels by the author.
This paper deals with the biography of the Hamburg-based chronometer maker Ferdinand Dencker (183... more This paper deals with the biography of the Hamburg-based chronometer maker Ferdinand Dencker (1837-1917) and his attempt to establish an industrial production of chronometers. One of his pendulum clocks (no. 35) was owned by the Göttingen University Observatory.
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Papers by Günther Oestmann
https://biblioscout.net/journal/stl/54/1
This is an expanded version, with references, of a lecture given by the author on 27 October 2021 in the “Runtingerhaus” in Regensburg.
https://biblioscout.net/journal/stl/54/1
This is an expanded version, with references, of a lecture given by the author on 27 October 2021 in the “Runtingerhaus” in Regensburg.