The Observational Instruments at the Maragha Observatory after AD 1300

The present paper introduces, investigates, analyses, and comments on an anonymous treatise in Persian named al-Risāla al-Ghāzāniyya fi ’l-ālāt alra ½×diyya, “Ghāzān’s (or Ghāzānid) treatise on the observational instruments”, which describes the structure, construction, and functions of twelve “new” observational instruments in the medieval period that appear to have been proposed and invented during the reign of Ghāzān Khān, the seventh Ilkhan of the Ilkhanid dynasty of Iran (21 October 1295–17 May 1304). In the sections below we consider the treatise in the light of two issues: (1) the assumption that the primary historical sources may contain interesting notes and claims concerning Ghāzān Khān’s astronomical activities and especially the new observatory that he founded in Tabriz, and (2) the fact that at present there are hardly any sound and historically reliable accounts of the activities of the Maragha Observatory from around 1280 onwards. It is thus essential to explore the issues that constitute the principal historical features of the research, i.e., Ghāzān, the Maragha Observatory, and astronomical activities, and to clarify the contextual relations between them. In what follows we present the key historical facts (derived from the primary sources) regarding Ghāzān and his connection to both astronomy and the Maragha Observatory. Second, we describe the Maragha Observatory in the period in question, giving further details about the observational programs conducted there and noting the substantial differences between them. These data cast new light on the activities of the observatory and, as we shall see below, may challenge the established history. We then examine the treatise, its contents, the manuscripts available, and the original approach applied to the design and construction of the instruments. In the final section, we examine the notes (and the possible misunderstandings as well) deduced from the treatise as regards the instruments, their physical construction, and their relation to Ghāzān and the Maragha Observatory. The section also contains two open discussions on the only possible archaeological evidence for the instruments and the authorship of the treatise. The most important evidence is, of course, provided by the instruments themselves and the new approach applied to their design and construction, which we discuss in the second part of the paper along with a classification of the different types of the instruments. We describe the configuration and functions of each instrument separately. These two sections are based on the text; a few changes in the order and arrangement of the materials are introduced to give a fuller account of each instrument in relation to the original text. These are followed by a separate section containing critical comments on the instrument with regard to either technical or historical considerations, including critical remarks such as probable mistakes or omissions in the treatise and some suggestions for corrections and completions, an analysis of our author’s claim concerning the superiority of a new instrument over its precursors, the applicability of each instrument, the comparison of a new instrument with similar historical counterparts, and so on

Más allá del paisaje: análisis de los sistemas de fosas circulares neolíticas de la Baja Austria con arqueoastronomía virtual avanzada

[EN] This paper describes developments in virtual archaeology that started in a research project about the possible astronomical entrance orientation of Neolithic circular ditch systems (German Kreisgrabenanlagen, KGA) of Lower Austria. Starting from data analysis in a Geographical Information System (GIS), we will cover a simple way of modelling, and discuss three ways of visualisation for the combination of landscape and human-made buildings together with celestial objects. The first way involves extensions to the modelling program SketchUp to bring in just enough astronomical data for scientific evaluation. The second introduces a set of extensions to the open-source desktop planetarium program Stellarium, which can meanwhile be used to load a standard 3D model format to allow detailed research in astronomical orientation patterns, and light-and-shadow interaction over many millennia, even for researchers less familiar with astronomical programming. The third presents a “serious gaming” approach, which can provide the most natural view of the landscape, but requires at least some, if not deep, familiarity with astronomical and 3D computer graphics programming and, therefore, due to this considerably larger effort, appears to be mostly useful for outreach of high-profile results to the public. The entrances to the KGA of Lower Austria turned out to be mostly oriented following a purely terrestrial pattern of up- and downward sloping terrain, but with one noteworthy exception.Highlights:Virtual archaeology can help to better understand archaeological remains embedded in the landscape. Occasionally, the “landscape” concept must be extended to include the celestial landscape.Open-source development allowed the combination of a desktop planetarium with 3D landscape and architecture visualisation. Also, datable changes in the landscape can meanwhile be simulated.Astronomical elements added to a game engine can also be used to faithfully provide important insights while providing the most appealing visualisation environments so far, but with considerably more effort.[ES] Este artículo describe los desarrollos en el campo de la arqueología virtual que se iniciaron en un proyecto de investigación sobre la posible orientación astronómica de la entrada de los sistemas de fosas circulares neolíticas (Kreisgrabenanlagen en alemán, KGA) de Baja Austria. Partiendo del análisis de los datos en un Sistema de Información Geográfica (SIG), cubriremos una forma sencilla de modelización, y discutiremos tres formas de visualización para la combinación de los paisajes y los edificios construidos por el hombre junto con objetos celestes. La primera forma implica extensiones del programa de modelado SketchUp que aporta sólo los datos astronómicos necesarios para la evaluación científica. El segundo introduce un conjunto de extensiones al programa de sobremesa, de código abierto y de planetario denominado Stellarium, que pueden utilizarse para cargar un formato de modelo 3D estándar que permita la investigación detallada de patrones de orientación astronómica y la interacción luz-sombra a lo largo de muchos milenios, incluso a investigadores menos familiarizados con la programación astronómica. El tercero presenta un enfoque de "juego serio", que puede proporcionar la visión más natural del paisaje, pero que requiere al menos cierta, si no profunda, familiaridad con la programación astronómica y de gráficos por ordenador en 3D y, por lo tanto, debido a este esfuerzo considerablemente mayor, parece ser mayormente útil para la divulgación de resultados destacados al público. Las entradas a la KGA de Baja Austria resultaron estar orientadas en su mayor parte siguiendo un patrón terrestre puro de terreno inclinado hacia arriba y hacia abajo, pero con una excepción digna de mención.Project ASTROSIM was funded by the Austrian Science Fund (FWF) under grant P21208-G19.Zotti, G.; Neubauer, W. (2019). Beyond the landscape: analysis of Neolithic circular ditch systems of Lower Austria with advanced virtual archaeoastronomy. Virtual Archaeology Review. 10(21):90-102. https://doi.org/10.4995/var.2019.10772SWORD901021021Atkinson, R. J. C. (1966). Moonshine on Stonehenge. Antiquity. https://doi.org/10.1017/S0003598X0003252XBecker, H. (1996). Kultplätze, Sonnentempel und Kalenderbauten aus dem 5. Jahrtausend vor Chr. - Die mittelneolithischen Kreisanlagen in Niederbayern. Arbeitshefte Des Bayrischen Landesamtes Für Denkmalpflege, 59.Beex, W., & Peterson, J. (2004). The Arminghall Henge: Space and Time: How Virtual Reality Contributes to Research on its Orientation. 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Retrieved from http://www.cg.tuwien.ac.at/research/publications/2005/kastowski-2005-kat/Kokalj, Ž., Zakšek, K., & Oštir, K. (2011). Application of Sky-View Factor for the Visualization of Historic Landscape Features in Lidar-Derived Relief Models. Antiquity, 85(327), 263-273. https://doi.org/http://dx.doi.org/10.1017/S0003598X00067594Lenneis, E. (Ed.). (2017). Erste Bauerndörfer - älteste Kultbauten: Die frühe und mittlere Jungsteinzeit in Niederösterreich. Vienna: Verlag der Österreichischen Akademie der Wissenschaften.Lockyer, N. (1906). Stonehenge and other British Stone Monuments Astronomically Considered. London: Macmillan and co.Magli, G. (2016). Archaeoastronomy: Introduction to the Science of Stars and Stones. Cham Heidelberg New York Dordrecht London: Springer International Publishing AG Switzerland. https://doi.org/10.1007/978-3-319-22882-2McCluskey, S. C. (2015). Orientation of Christian Churches. In C. Ruggles (Ed.), Handbook of Archaeoastronomy and Ethnoastronomy (pp. 1703-1710). New York: Springer. https://doi.org/10.1007/978-1-4614-6141-8_173Meeus, J. (1998). Astronomical Algorithms (second). Richmond, Virginia: Willmann-Bell.Melichar, P., & Neubauer, W. (Eds.). (2010). Mittelneolithische Kreisgrabenanlagen in Niederösterreich. Österreichische Akademie der Wissenschaften.Neubauer, W. (2017). Kreisgrabenanlagen (4850/4750-4650/4500 BC). In E. Lenneis (Ed.), Erste Bauerndörfer - älteste Kultbauten: Die frühe und mittlere Jungsteinzeit in Niederösterreich (pp. 276-297). Vienna: Verlag der Österreichischen Akademie der Wissenschaften.Pásztor, E. (2008). Megjegyzések a Lengyeli Kultúra Körárkainak Tájolásához (with German abstract: Bemerkungen zur Orientierung der Kreisgräbern der Lengyel-Kultur). Archaeologiai Értesítő, 133, 5-20.Pavúk, J., & Karlovský, V. (2004). Orientácia Rondelov Lengyelskej Kultúry na Smery Vysokého a Nízkeho Mesiaca. 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Kreise und Kulturen - Kreisgrabenanlagen in Mitteleuropa. In F. Daim & W. Neubauer (Eds.), Zeitreise Heldenberg - Geheimnisvolle Kreisgräben (pp. 10-18). Horn, Wien: Verlag Berger.Vondrák, J., Capitaine, N., & Wallace, P. (2011). New precession expressions, valid for long time intervals. Astronomy and Astrophysics, 534(A22), 1-19. https://doi.org/10.1051/0004-6361/201117274Vondrák, J., Capitaine, N., & Wallace, P. (2012). New precession expressions, valid for long time intervals (Corrigendum). Astronomy and Astrophysics, 541(C1). https://doi.org/10.1051/0004-6361/201117274eZotti, G. (2005). Kalenderbauten? -- Zur astronomischen Ausrichtung der Kreisgrabenanlagen in Niederösterreich. In F. Daim & W. Neubauer (Eds.), Zeitreise Heldenberg: Geheimnisvolle Kreisgräben --- Niederösterreichische Landesausstellung 2005 (pp. 75-79). Horn, Wien: Verlag Berger.Zotti, G. (2006). A sky dome visualisation for identification of astronomical orientations. 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Open-Source Virtual Archaeoastronomy. Mediterranean Archaeology and Archaeometry, 16(4), 17-24. https://doi.org/10.5281/zenodo.207260Zotti, G. (2017). Sonnen- oder Talwärts? Die Orientierung der Zugänge der jungsteinzeitlichen Kreisgrabenanlagen Niederösterreichs. In E. Lenneis (Ed.), Erste Bauerndörfer - älteste Kultbauten: Die frühe und mittlere Jungsteinzeit in Niederösterreich (Vol. 1, pp. 297-306). Wien: Verlag der Österreichischen Akademie der Wissenschaften.Zotti, G., & Neubauer, W. (2010). Astronomische Aspekte der Kreisgrabenanlagen Niederösterreichs. In P. Melichar & W. Neubauer (Eds.), Mittelneolithische Kreisgrabenanlagen in Niederösterreich (pp. 136-167). Vienna: Österreichische Akademie der Wissenschaften.Zotti, G., & Neubauer, W. (2015). Astronomical and Topographical Orientation of Kreisgrabenanlagen in Lower Austria. In F. Pimenta, N. Ribeiro, F. Silva, N. Campion, A. Joaquinito, & L. 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Simulation of astronomical aspects of Middle Neolithic circular ditch systems

Introduction The oldest Middle European monuments (approx. 4850/4750 – 4550/4500 BC) were presented in the Lower Austrian County Exhibition at Heldenberg in 2005 (Daim & Neubauer, 2005). The Middle Neolithic circular ditch systems, or Kreisgrabenanlagen (KGA), are known all over Middle Europe. These wooden monuments form a first pan-European phenomenon, crossing the cultural borders defined by the archaeological material record. One third of the approx. 135 monuments known so far are found in..

Beyond Paradigms in Cultural Astronomy. Proceedings of the 27th SEAC conference held together with the EAA

Proceedings of the 27th SEAC conference held together with the EAA.-- Editors: A. César González-García, Roslyn M. Frank, Lionel D. Sims, Michael A. Rappenglück, Georg Zotti, Juan A. Belmonte, Ivan Šprajc.Cultural Astronomy is the endeavour to understand the role of the sky in past and present societies, and how these societies incorporated the sky into their culture. This broad ranging discipline is closely related to archaeology when investigating material remains of the past. Cultural Astronomy also explores the role of the heavens from the perspectives of the anthropological sciences. In recent decades the discipline has been concerned with methodological and theoretical issues. This volume offers chapters based on presentations at the 27th SEAC meeting held in Bern (2019). These chapters provide a vivid image of front-line research in diverse areas, from Roman light and shadow effects to highlight power, to Maya city organization, Etruscan temple orientation or the ontology of the sky.Peer reviewe

Computer graphics in historical and modern sky observations

Zsfassung in dt. SpracheThis PhD thesis contains three aspects of sky observations in combination with computer graphics.The first part describes a novel diagram for research in archaeo-astronomy. It provides an intuitive visualisation for the analysis of archaeological survey maps with respect to astronomically motivated orientation of architectural structures. The analysis of Neolithic circular enclosures of Lower Austria indeed indicated the orientation of doorways towards certain rising or setting points of the sun and selected stars, which can be further explained as having a practical purpose. The presentation of results like this towards the general public by combination of virtual reconstructions and the sky simulation in a modern Planetarium is described in the following chapter.The topic of the second part is the astrolabe, the iconic instrument of the Middle Ages for astronomical observation and computations. The author describes the construction of the astrolabe by methods of procedural modelling, where, instead of modelling each line explicitly, the geometric drawing is encoded in parametrized drawing rules which are then executed with the appropriate parameter set. The resulting 2D plots are optimized for print, and can also be used for driving a laser engraver to build instruments for hands-on demonstration in cultural heritage events.The third and longest part deals with methods of sky simulation, rendering and capturing from the proper area of computer graphics. After an extended survey of the literature with many links from atmosphere physics, results from own sky luminance measurements are presented and compared to existing analytic models of the sky luminance, which shows that the model currently in widest use has significant shortcomings.Hereafter, a calibrated photgraphic measurement system for capturing skylight is presented. The high dynamic range images generated can be used as scene backgrounds or for image based lighting in computer graphics renderings. However, the calibrated luminance channel allows applications in other fields, like the quantitative evaluation of nocturnal sky glow caused by urban light pollution. Some results are presented, and the implementation is described in an appendix.The thesis closes with ideas for future work and some technical developments expected in the near future.Diese Arbeit behandelt drei Aspekte von Himmelsbeobachtungen in Kombination mit Computergraphik. Der erste Teil behandelt ein neuartiges Diagramm für die Archäo-Astronomie, das eine intuitive Visualisierung zur Untersuchung archäologischer Vermessungspläne auf Hinweise astronomisch motivierter Orientierungen von markanten Sichtlinien bietet. Eine darauf gestützte Untersuchung der jungsteinzeitlichen Kreisgrabenanlagen Niederösterreichs erbrachte tatsächlich klare Hinweise auf derart astronomisch motivierte Ausrichtung von Zugangstoren einiger dieser Anlagen, denen auch eine praktische Funktion zugeordnet werden kann. Die publikumsgerechte Aufbereitung der Ergebnisse durch Kombination virtueller Rekonstruktion mit der Himmelssimulation in einem modernen Planetarium ist Thema des folgenden Kapitels.Der zweite Teil der Arbeit behandelt das Astrolabium, das astronomische Beobachtungs- und Recheninstrument des Mittelalters schlechthin. Zur Nachbildung dieses Paradebeispiels mathematisch-geometrisch konstruierter Instrumente mit Methoden der prozeduralen Modellierung wird die Konstruktionsanleitung in Prozeduren umgesetzt, die zur Erzeugung eines konkreten Instruments mit unterschiedlichen Parametern ausgeführt werden. Aus diesen 2D-Graphiken können 3D-Modelle und -- mittels Lasergravierer -- auch Instrumente aus Holz gefertigt werden.Der dritte und längste Teil behandelt Methoden der Himmelssimulation, -darstellung und -erfassung aus dem Kernbereich der Computergraphik. Nach einer ausführlichen Literaturübersicht mit Querbezügen zur Literatur aus der Atmosphärenphysik wird anhand von Helligkeitsmessungen am klaren Himmel gezeigt, daß das derzeit meistverwendete analytische Himmelsmodell Mängel aufweist.Danach wird ein kalibriertes photographisches Meßsystem zur Erfassung des Himmels präsentiert. Damit gewonnene ``High Dynamic Range''-Aufnahmen finden als Bildhintergrund für Außenszenen und ``image based lighting'' in der Computergraphik weite Anwendungen, können aber auch zur Untersuchung und Quantifizierung der nächtlichen Himmelshelligkeit und urbanen Lichtverschmutzung verwendet werden. Ergebnisse dieses Systems werden hier vorgestellt, die notwendigen Arbeitsschritte werden in einem Anhang beschrieben.Die Arbeit schließt mit einigen Ideen für zukünftige Forschungen und einem Ausblick auf zu erwartende technische Entwicklungen.17

A Sky Dome Visualisation for Identification of Astronomical Orientations

Figure 1: Virtual reconstruction of a look through one of the doors in the neolithic Kreisgrabenanlage of Steinabrunn in Lower Austria. The singular post appears to be aligned to the rising point of the Pleiades star cluster, which with their rising in the morning shortly after spring equinox possibly announced the beginning of the agricultural year. Astronomical alignments like this have been identified using the method described in this paper. Screenshot from StarryNight Pro 4.5, foreground from virtual reconstruction courtesy of Imagination Computer Services, Vienna. It has long been known that ancient temples were frequently oriented along the cardinal directions or to certain points along the horizon where the Sun or the Moon rises or sets on special days of the year. In the last decades, archaeologists have found evidence of even older building structures buried in the soil, with doorways that also appear to have distinct orientations. This paper presents a novel diagram combining archaeological maps with a folded-apart, flattened view of the whole sky, showing the local horizon and the daily paths of the Sun, Moon and brighter stars. By use of this diagram, interesting groupings of astronomical orientation directions, e.g. to certain sunrise and sunset points could be identified, which were evidently used to mark certain days of the year. Orientations towards rising and setting points of a few significant stars very likely indicated the beginning of the agricultural year in the middle neolithic period