Picture of the Month - December 2007

If you take a picture of the Sun at the same time each day for a year, would it remain in the same position? The answer is no.

The shape traced out by the Sun over the course of a year is called an Analemma. The Sun's apparent shift is caused by the Earth's motion around the Sun when combined with the tilt of the Earth's rotation axis. Earth does not move around the Sun in a perfect circle. The Earth's orbit is rather elliptical. So at some part of the year Sun is closer to the Earth and at some part it is farthest. Earth's axis is tilted at an angle of 23° which gives out seasons. During summer the Sun will appear at its highest point of the analemma and lowest during winter.

Analemmas created from different Earth latitudes would appear at least slightly different, as well as analemmas created at a different time each day. The analemma pictured on top was built up by Sun photographs taken from 1998 August through 1999 August from Ukraine. The foreground picture from the same location was taken during the early evening in 1999 July.