Solar Analemma 2015

Giuseppe Petricca
Location of photo
Sulmona, Abruzzo, Italy
Date/Time of photo
04/01/2015 - 12:00 UTC
Nikon Coolpix P90 Bridge - Astrosolar
This strange figure, with a shape of an 8 or an infinite, the analemma, is caused by the axial tilt of our planet, and by the elliptical shape of our orbit around the Sun. If we take a picture day by day, always at the same hour, the Sun is not in a fixed position, but it slowly clibs up and then down the curve. If the Earth had a circular orbit and its axis was at 0° tilt the analemma would not exist, since the Sun will be always in the same place in the sky at a determined hour of the day. If the orbit was circular, but the axis was tilted like our real one, the two lobes of the figure would be equal in dimensions. Instead, if the orbit was elliptical (like in the reality) and the axis was not tilted, the analemma would be only a line that would go from east to west.
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