A heliodon is a device used to simulate the movement of the sun relative to the earth’s surface.  Our heliodon, completed for display at the 2006 Kentucky State Fair, has helped students, professionals and the community understand how the sun moves through the sky and how proper design for a particular climate can improve the performance of passive solar heating systems.

The heliodon is relatively lightweight and portable.  The heliodon can  simulate the movement of the sun  with adjustments for latitudes from near 0° (the equator) to 65° (mid Alaska) and for the full range of declination (summer solstice to winter solstice). The light source swings through an entire day with hour angles from sunrise to sunset.  It uses a Fresnel lens to simulate the virtually parallel rays of the sun and supports up to an approximately 18”w x18”d x 12” tall model.