A new approach to heliodons: A four-axis prototype capable of operating under varying altitude light sources

摘要

Heliodons have long been regarded as invaluable tools for examining the interplay of solar geometry and the built environment. Typically used in conjunction with physical scale models, heliodons generally comprise a rotating table and a fixedsource, or a stationary table and an 'orbiting' light system that mimics the sun's apparent movements. Three-axis rotating table heliodons offer the most flexibility and accuracy and enable users to quickly visualize their designs under the full range ofsolar aspects. Unfortunately, three-axis heliodons generally have their rotational indicators angularly referenced to a fixed 'altitude' light source. Such a setup limits the versatility of the heliodon by fixing its location with respect to the source,making it difficult to use under real sun or with electric light sources of 'altitudes' dissimilar to that of the originally intended operation location. This paper describes a simple four-axis heliodon which overcomes these limitations.