This 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.