Prof. Dr. Klaus Geus (Organizer)

Ancient Sundials, Astronomical Instruments and Geographical Knowledge

22th–24th, September 2011, Freie Universität Berlin

 

Alexandr Podossinov (Moskow, RUS): „Wohin fuhr Odysseus? Große Meereengen im archaischen Weltbild der Griechen“ For the most part ancient historians deny that ancient seamen could reach the Okeanos, the ocean that surrounds the Oecumene and dismiss accounts of them so doing as fairy tales. Nevertheless, the voyages of Odysseus, the Argonauts, Hercules and other heroes shaped the archaic perception of space. The Greeks deemed the Okeanos to be navigable. Via the great straits one could leave the “real” world and end up in the otherworldly realm of the nether regions and Hades or make the “shortcut” to the other side of the Oecumene. This explains at lot of paradoxa in Greek mythographical and geographical texts.

Eva Winter (München): „Die handliche Zeit. Zum Einsatz von Miniatur- und Reiseuhren“ Eva Winter won her postdoctoral degree last year at the university of Munich with a thesis on „Zeitzeichen – Zeitmessung und Zeitanzeige in Hellenismus und Kaiserzeit“ which also includes a corpus of ancient sundials. In her paper “Die handliche Zeit. Zum Einsatz von Miniatur- und Reiseuhren“ she discussed some 20 items small (20 cm or less) “portable” sundials and interpreted them as objects not only of geographical but also, and rather more, of symbolic and cultural value. The group of owners may be identified with the agents of Romanization in the Imperium Romanum.

Stefano Magnani (Udine, IT): „Die Welt in einer Ecke. Die Breiten-bestimmung von Massalia und ihr Einfluss auf die hellenistische Kartographie“ At the end of the 4th century BC, the astronomer Pytheas of Massilia traveled to many European regions and made measurements of dif-ferent parts of the Oecumene with the help of a gnomon. This instru-ment helped him not only to measure time but also to define geo-graphical position on the surface of the earth. Pytheas´ observations made a huge impact on later astronomer like Eratosthenes, Hipp-archus or Ptolemy. Their maps depend to a great extent on Pytheas´ accomplishments.

Wolfgang Hübner (Münster, GER): „Edmund Buchners Sonnenuhr und die Sternbilder des Augustus“ Seemingly, the horologium Augusti discovered by Edmund Buchner contained nothing other than a meridian, like those that were constructed during the Renaissance in Italy and elsewhere. Buchner's theory which relates Capricorn and Libra, zodiacal signs that are nine months apart, with the conception and birth of the emperor on one hand, and with the burial in the Ustrinum and the funeral in the Mausoleum, on the other is no longer sustainable. We have to look for other reasons to explain this difference. In his iconographical pro-paganda Augustus preferred Capricorn over Libra (Balance), ex-uberantly proposed to him by Vergil, although Libra, by its own symbolic connotation, was regarded as the sign of Italy, and although Augustus is said to have been born on September, 23rd. In the earliest run of coins a very small Capricorn is contrasted with a huge crocodile, constellation of Egypt, which may be a gesture of understatement. Second, Capricorn, situated on the winter solstice, inaugurates the sun´s rising from the deepest point of its course, and so, following a special astrological lore, it “regards only itself”, a kind of self-satisfaction that has been related to the emperor's autarky by the poet Manilius. Third, Libra and Capricorn are accompanied both by the extrazodiacal paranatellonta Lyra (or Fides) and Sagitta that form a heraclitean πίντροπος ἁρμονία, and through this the Balance recovers its symbolic value: The Arrow is said to rise together with Libra at 8°, considered to be the accurate autumnal equinox at that time. According to Manilius, Libra and Sagitta together produce skilful archers like the Homerian Teucer, whose name had been adopted by the astrologer Teucrus with regard to his 'stochastic' art. It was just near the autumnal equinox that Hipparchus discovered the precession of the equinoxes by observation of Spica (α Virginis). Thus, both fan-

ciful astrological combination and astronomical scrutiny, point to the same delicate degree of the ecliptic.

Richard J. Talbert (Chapel Hill, USA): „The Roman world reflected in portable sundials“ One type of portable sundial from classical antiquity offers an hitherto unrecognized category of testimony for penetrating the ancient world-view. In what is a no more than passing reference, Vitruvius characterizes these dials as viatoria, pensilia (“for journeys,” “hanging”), and much discussed (for their time-keeping, no doubt). The paper reviews the dozen or so known examples (some inscribed in Greek, others in Latin), and briefly discusses the difficulty of dating them. It then proceeds to analyze the instructive variety of city- and regional names attested on them, each with a corresponding (and barely standardized) latitude figure. The purpose(s) for which these dials were designed, and the nature of the worldview embedded in them, are the paper’s key concerns.

Daryn Lehoux (Queen´s University, Kingston, CN): „Reflectance Transformation Imaging (RTI) and Astronomical Inscriptions“ Reflectance Transformation Imaging (RTI) is a powerful yet easy to use and inexpensive digitization technique that promises to transform the way epigraphy is done and how digital records of inscriptions are archived. This talk introduced RTI to historians of astronomy, and presented preliminary results from Lehoux´s recent work on astro-nomical inscriptions in the “Antikensammlung” in Berlin.

Karlheinz Schaldach (Schlüchtern, GER): „Towards a corpus of Graeco-Roman sundials“ Karlheinz Schaldach who is currently working on a corpus of Greco-Roman sundials, showed some of his new findings and results. Among them are hitherto undiscovered lines on the walls of the Tower of the Winds in Athens, Andronicus´ northern clock on the island of Tenos and a „Greek“ sundial found near the Mosel in Germany. Schaldach also made some interesting propositions for an innovative web-based data base of ancient sundials.

Gerd Graßhoff and Elisabeth Rinner (Berlin, GER): „The usage of sundials for the data of Ptolemy's Geography“ In his Geography from the second half of the 2nd century AD, Ptolemy suggests systematic measurements of geographical latitudes by astronomically trained people as the best way to determine latitudes of

geographic coordinates. Such measurements, for example, could be made by observing the position of the sun or the length of its shadow at noon. By proceeding like this, one could make use of the same type of data, on which the layouts of sundials depend upon. Based on an analysis of data for Asia Minor it is shown that Ptolemy did not use such observational data, but based his Geography on the latitudes of a very few reference places, which he found within the texts cited of Hipparchus. Furthermore, it is argued that despite the fact that these latitudes are represented by values which could result from astro-nomical observations, the data is, in fact, the result of measurements of distances.

Robert Hannah (University of Otago, NZ): „Meridians, the Horologium Augusti and the Pantheon“ In this paper Robert Hannah first sought to re-establish the capacity of the Horologium of Augustus to serve as more than just a meridian line, and to speculate on its symbolic value. Then he examined the role of the sun in the Octagonal Room of Nero’s Domus Aurea and in Hadrian’s Pantheon, concentrating on its presence and metaphysical significance at noon at certain times of the year. Both the Octagonal Room and the Pantheon arguably make a great deal of play with the equatorial, or more specifically equinoctial, part of the sky, and through that play may have sought to raise the emperors above the ordinary and into the company of the gods. If this is so, it would seem that what had taken Augustus several monuments scattered on the Campus Martius to make a unified statement about his cosmically ordained role in bringing the Roman world to peace – the Horologium, the Ara Pacis and the Mausoleum – Nero and Hadrian achieved in a single interior space.

Irina Tupikova (Lohrmann-Observatorium, TU Dresden, GER): „Mo-delling Ancient Sundials“ Three systems of celestial coordinates, the equatorial, horizontal and ecliptic, as well as their projection on the shadow-receiving plane define the geometry of sundials. A new method was proposed to model planar sundials with arbitrarily oriented planes and shadow-producing parts based on a simple vector equation in combination with the application of the sequences of rotational matrices. This method allows the construction of shadow maps for sundials with errors produced by false determination of geographical latitudes or by erroneous con-struction. Applications for modelling some ancient sundials (Tower of

Winds, Athens; The Amphiareion Equatorial Sundial, Piraeus) were considered and their shadow maps discussed.

One of the most astonishing, but nevertheless universally accepted results of the conference, was that the primary function of ancient sundials was not to tell time accurately but rather to synchronize the social life of collectives and communities.

Text: Klaus Geus

 

 

gehe zurück

 

<< zur Homepage des Arbeitsbereiches