An <a href="https://en.wikipedia.org/wiki/en:analemma" class="extiw" title="w:en:analemma">analemma</a> or solar <a href="//commons.wikimedia.org/wiki/Category:Lemniscate" title="Category:Lemniscate">lemniscate</a> is the curve in the shape of a <a href="//commons.wikimedia.org/wiki/Category:Figure_eight" title="Category:Figure eight">figure-eight</a> that traces the Sun in the daytime sky throughout the year (each day at the same time as it slowly changes its position in the sky). Fixing a camera to a tripod and every 10 days <a href="//commons.wikimedia.org/wiki/Category:Chronophotography" title="Category:Chronophotography">multiply-exposing</a> a photo allows one to "graph" such a curve.
<p>Different forms of the curve arise due to the inclination of the planet's axis with respect to the plane of its orbit and the orbital eccentricity itself.
</p><p>Here the Martian analemma (it is not a lemniscate, but another curve) is wider since the eccentricity of the red planet is greater than the terrestrial one and a little higher above the horizon because the inclination of its axis with respect to its plane Orbital is also greater than that of Earth. This inclination is called "<a href="//commons.wikimedia.org/w/index.php?title=Category:Obliquity&amp;action=edit&amp;redlink=1" class="new" title="Category:Obliquity (page does not exist)">obliquity</a> of the ecliptic".
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If one of the two planets had an orbit that was a circle and its inclination level, every day at the same time it would be observed in the same point of the sky; neither a lemniscate nor any other curve would be observed. If the orbit were circular but the inclination off-level, a vertical line coinciding with the meridian line would be drawn throughout the year.
<a href="//commons.wikimedia.org/wiki/User:Fernando_de_Gorocica" title="User:Fernando de Gorocica">Fernando de Gorocica</a>
CC BY-SA 3.0
<span class="int-own-work" lang="en">Own work</span>