The geometry of object’s exposure to solar radiation at various points on the Earth’s surface is based on spherical geometry. Due to the angle of the Earth’s axis (declination) the Earth experiences seasons. Seasons are a consequence of energetic radiation reaching the surfaces of the Earth. This geometrical particularity and its effect are not easily understandable. In order to make the topic as accessible as possible, various tools (such as the heliodon) were created to make understanding solar exposure and shading simpler.
The heliodon structure is around 1 x 1 m (the hoop for the sun’s orbit), making it possible to easily transport to a lecture hall for demonstration purposes. The sun is represented by an adjustable LED light with as many targeted lighting characteristics as possible, allowing it to be adjusted manually for each season, time of day and geographic latitude. By changing the individual parameters the effect on sun exposure and shading is immediately visible and understandable.
Objects can be placed on the central platform. Many objects (wooden building blocks, model trees) are found in, and can be taken from, the box of building blocks. A small, integrated video camera allows the presentation of the results to be seen in large lecture halls with large audiences; however direct use by students in the form of an assignment is ideal.
The heliodon, user handbook, and box of model building blocks can be used for demonstration purposes in a lecture or loaned out for use in seminar courses and practical exercises.