In this StarDate Susitna Kathleen Fleming talks about the full moon of December, our gloriously long nights, the Geminid meteor shower, and other astro-topics.
The Analemma. A full description of this figure and the Equation of Time can be found on-line. Image from analemma.com.
The equation of time — above the axis a sundial will appear fast relative to a clock showing local mean time, and below the axis a sundial will appear slow. (from Wikipedia entry for “Equation of Time”
After 24 hours, if you were standing on Earth “A” looking at the sun, it would appear to be directly overhead. If you were standing on Earth “B” looking at the sun, it would appear NOT to be directly overhead. Earth “B” has not quite rotated far enough relative to the sun. If you were looking at your watch on Earth “B” and comparing its time to the position of the sun, it would appear that the sun’s position would be slightly to the east. After another 24 hours Earth “B” is still continuing to move faster than average. This error in time will accumulate and the sun will continue for a time to appear to move farther and farther east in the sky, again, in comparison to what your watch reads at noon. (diagram and text a portion of the very interesting pages at analemma.com)
