Movement of the Sun
Passive solar design relies upon the movement of the sun’s path in the sky through the seasons.
The Earth is rotating around the sun, however, as our planet spins and rotates around the sun, it appears to the inhabitants of Earth that the sun is moving across the sky. Thus, it is often referred to as the ‘movement of the sun’.
Pinhole photography artist Justin Quinnell strapped a camera to a telephone pole and recorded the sun’s movements from December 17, 2007, to June 21st, 2008.
In the picture below, trace the shortest arc (representing the path of the winter sun) and contrast that with the longest and highest arc that shows the sun’s path on the summer solstice.
The sun travels its shortest and lowest arc through the sky on the winter solstice. The low winter arc allows the sun’s rays to reach deep into a structure to warm it on a cold winter day. On the summer solstice, the sun travels its highest and widest arc through the sky. If the building is designed with an overhang or some type of blocking mechanism, the sun heat energy will be blocked and the building will stay cool.
When considering a retrofit for my old stone house, I took pictures of the sun, as well as of how the sun’s light interacted with the house on both the winter and summer solstices.
In regard to these pictures, amazingly, a single sheet of photography paper recorded the sun’s travels for a year through a 25mm aperture in a handmade pinhole camera made out of a empty drink can.
For more information on Justin Quinnell’s photography, visit the artist’s website http://www.pinholephotography.org/
While the sun appears to rotate around us, in actuality, the earth is rotating around the sun.