12 days ago
By Marc Dancer
If you could observe the sun at exactly the same time each day, would it appear in the same place? Amazingly, the answer is no. The shape traced out by the sun over the course of the year is called an analemma. Two elements combine to produce this elegant figure-eight curve; the variation in speed as the earth moves around its elliptical orbit about the sun and the tilt of the earth. During the Summer Solstice the sun is at its highest point in the sky. When using a skylight to observe the analemma pattern, this translates into the lowest point on the curve.
Pictured here is the analemma skylight in the Koch Center Starfield, photographed on June 20th–the longest day this year.