OPEN-SOURCE VIRTUAL ARCHAEOASTRONOMY

A large fraction of archaeoastronomical surveys is concerned with the evaluation of azimuth orientations of artificial, or sometimes natural, structures to find a correlation with potential astronomical targets, like sunrise/sunset, or the interplay of light and shadow at particular dates like the solstices. Given the difficulties of observing such a structure during months or even years, it seems very desirable to record or reconstruct the structure in question and bring a virtual 3D model into a computer system capable of accurately rendering the sky, the model, and light and shadow effects depending on proper astronomical simulation, also including the situation at other times. Applications for such a system can be manifold. Horizon panoramas in various desktop planetarium programs have already previously allowed assessment of single-viewpoint observations with proper horizon altitudes. But the ability to load a properly georeferenced and accurate 3D model into virtual space and identify and observe sight lines combined with a recreation of past skies, or to observe light and shadow effects that would change over weeks and months within just minutes of simulation, should allow much better understanding of the potential use of such structures, and can clearly illustrate and demonstrate these phenomena also for a wider audience. Likewise, an archaeologically sound virtual reconstruction beyond today’s often deteriorated state can be used to recreate the likely appearance of the site in past times. A few such installations can be seen in museums, but none of them are widely available. The author has initiated development of a plugin for the popular open-source desktop planetarium Stellarium to allow research on 3D virtual reconstructions which has recently been greatly refurbished and integrated into the regular distribution of Stellarium. The paper also describes other contributions made by the author towards application of Stellarium for research and communication of cultural astronomy.