Analemma - a record of movement of the celestial spheres inaccessible to human senses. The ability to capture analemma is available only for persistent, consistent, patient, having astronomical knowledge ones. Analemma arises when during whole year, every day and exactly at the same time one records the position of the Sun in the sky. It's like going to the gym daily: each day the muscles repeat the same movements thousands times creating the effect. Visible effect. After the result, we can imagine the amount of work. As people treading path in the grass. As a recess in a chopping board. As wiping stone steps in old churches caused by putting feet in the same place y different people for centuries. For this you can compare cathing the analemma.
The analemma has both aesthetic and scientific values. Visually, at first glance, you can see a big figure eight in the sky. The shape of this figure, however, is determined by the celestial mechanics. By the laws of physics, which are valid for all objects in the universe. All atoms, molecules, living creatures, planets, stars and galaxies. To understand the mechanisms that govern the shape of analemma one needs mental effort, which opens further and deeper areas of aesthetics, stored in the structure of the Universe . It's as if the glass balls scattered randomly form pattern. Pattern which is stable and reproducible, but visible only at certain moments and in certain places only for someone who knows how to look. The atoms which are diffused randomly organizing themselves under the laws of physics in an increasingly hierarchic structure. No longer single atoms, but the stars, planets, people, which are the subject to the eternal laws of motion. Earth, as one of the planet, is on such and not another orbit, with such and no other period of revolution, orbit ellipticity, inclination of the axis and period of rotation. These periods and shapes affect shape of the analemma. Shape which is present and unchanged in the sky for centuries. Present shape in the form of long formulas and charts only for the elect, registered in the photograph for the first time in 1979 by Dennis di Cicco  and a few later. Apparently more people have stand on the lunar surface than have successfully photographed the analemma . More about the analemma can be found in Wikipedia.
The theory of the formation of the analemma has already been presented on many websites, so there is no need to repeat it here. A clear description can be found at: www.analemma.com.
 - More advanced readers can trace the physics and mathematics governing the shape analemmy in the paper of Charles H. Holbrow Build Your Own Analemma.
 - Dennis di Cicco, Exposing the Analemma, Sky and Telescope, 57 (June 1979) 536-540.
 - http://petapixel.com/2011/09/20/more-people-have-walked-on-the-moon-than-have-captured-the-analemma/