Sun Simulator Heliodon

This Sun Simulator was commercially available in Korea.

This Sun Simulator was built at the Architecture Faculty at Chiang Mai University in Thailand.

The first sun simulator was built at Auburn University in Alabama.

The Sun Simulator heliodon is conceptually clear because it imitates our everyday experience of the sun passing across the sky-dome, and the model being fixed on a horizontal ground plane. It is a large device usually greater than 10 ft (3 m) in diameter that cannot be easily moved. Although it is built for a particular latitude, the model support table can be tilted plus or minus 5 degrees yielding a 10 degree latitude range without loss of clarity (i.e. the architectural model is essentially still horizontal). Because of annual symmetry, only seven arches are needed to simulate the 21st day of all 12 months. For example, only one arch is needed to define the sunpaths for both November 21 and January 21. The Sun Simulator has a light for each hour of daylight for each month. The switches that control these lights can be located on a control panel, in a wired remote control, or a wireless remote control.

Sun Simulator Heliodon

Because it simulates our everyday experience of the sun moving across the sky-dome, the Sun Simulator heliodon is extremely intuitive and conceptually clear. Since its lights are fairly far from the model, its accuracy is quite good. The further the lights are from the model the more parallel are the light rays when they reach the model on the support table. The large size also allows the use of fairly large architectural models, and it allows many people to simultaneously observe the simulation.

The Sun Simulator’s large size is also its greatest disadvantage. Significant building space must be allocated for its use. For a 10 ft (3 m) heliodon a floor area of 15 x 15 ft (4.5 m) is required, and still larger heliodons are better. However, it is ideal for a public space such as a lobby if the space can be dimmed when necessary.  In such a space, the heliodon acts as both a piece of sculpture as well as a teaching tool.  It teaches the most important aspects of solar geometry even when its lights are not on.   The Sun Simulator heliodon must be built locally from free CAD drawings available through this webpage.


Free CAD drawings are available from Norbert Lechner for several latitudes.  The drawings can also be easily modified for any latitude.


Contact:   lechnnm@auburn.edu

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