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Details:
If observed at the same time each day, in the course of a year, the Sun's position in the sky traces a figure-8 shaped curve called the "analemma". The analemma is produced by the combined effects of the Earth's tilted axis of rotation and its variation in speed along its elliptical orbit around the Sun. Over the year, the Earth's axial tilt shifts the Sun's position north/south and the Earth's elliptical orbit shifts it east/west. Solstices correspond to the top and bottom of the figure-8, indicating the northern and southernmost limits of the Sun in the sky. The cross-over point on the curve is around both April 12 and August 30 as the Sun's apparent position ascends and descends respectively. The analemma curve is also a graphical representation of the equation of time which describes the difference between sundial time (apparent solar time) and clock time (mean solar time).
This is a composite image of the analemma, consisting of 38 separate solar exposures from September 20, 2013 to September 13, 2014 and 1 foreground exposure on August 11, 2014, all on a SINGLE FRAME OF FILM. Each solar image was taken at 9:50 AM at St. George's Crescent in Edmonton, Alberta, Canada.
All images were taken using a Canon A-1 film camera with a 28mm focal length lens. The solar images were typically at 1/125 sec at f/22, ISO 200. The camera was mounted on a tripod head affixed to a custom wooden mount that was placed on a park bench.
Photographer's website:
http://www.vanzella.com/analemma.html
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