Analemma for Greece
January 23, 2003
Provided and copyright by: Anthony Ayiomamitis
Summary authors & editors: Anthony Ayiomamitis; Jim Foster
The above photo is a splendid montage showing the changing position of the Sun in the sky over the course of a year, as seen from the Parthenon in Athens, Greece. The first image was taken on January 12 and the final (bottom-most) image on December 21 - there are a total of 41 photos.
"Analemma" is a word originally derived from the Greeks to mean prop or support, and it's Latin for the pedestal of a sundial, and hence the sundial itself. It seems that on only about a half dozen occasions, including this photo, has the anlaemma been successfully imaged as a multi-exposure on a single piece of film! An analemma is basically the figure "8" loop that results when one observes the position of the Sun at the same time during the day, over a 12 month period. As a result of the Earth's tilt about its axis (23.5°) and its elliptical orbit about the Sun, the location of the Sun in the sky is not constant from one day to another, even when observed at the same time each day. Furthermore, the figure 8 loop will be inclined at different angles depending on one's geographical latitude.
When the analemma curve is positioned upright, as it is above, it becomes a miniature almanac. The vertical coordinate of each point on the analemma gives the Sun's declination on a particular day of the year, while the horizontal coordinate tells how much the Sun is ahead of or behind clock time on that day.
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