from the website of National Geographic , beautiful photos showing the path of the sun in the sky:
summer the Sun is higher than the winter horizon and the phenomenon is due to the inclination of the Earth to the plane of its orbit around the Sun But there is another variation.
With a sundial is possible to determine the transit time of the Sun at the meridian of the place where we are, while the corresponding true local solar noon. Each interval of one hour solar marked on its face represents an increase of the Sun's hour angle of 15 ° (360 ° / 24 = 15 °).
If we measure time intervals between two successive transits of the Sun at the same meridian, however, that we would see not have equal intervals, but vary gradually during the year. This is because the motion (apparent) day of the Sun is not uniform but varies between a maximum and minimum speed. The orbit, tilted about 23 ° .5 respect to the equatorial plane is covered by our planet with a speed that is maximum at perihelion and least at aphelion. The consequence is the change in the duration of true solar days.
The perception of the difference between solar time and mean you watching the Sun every day at the same time . You will see that the Sun's position varies from day to day in both height and "sideways" to form a figure that Analemma or lemniscate, which is what you see in the photos.
The photographer has made by placing the camera at different times of the year at the same time. By overlaying the images obtained reproduced those obtained here. The word comes from greek analemma and means the pedestal base of a sundial.
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