Analemmas
An analemma is the figure-eight curve that the Sun traces in the sky when its position is recorded at the same clock time every day for a year from a fixed location. The shape arises from two orbital effects: the tilt of Earth's axis relative to its orbit (obliquity) and the eccentricity of its orbit. The tilt makes the Sun’s daily path drift north and south across the sky through the year, while the irregular speed of Earth's orbit causes solar noon to occur slightly earlier or later than the clock time. When the Sun’s altitude and azimuth are plotted for a fixed time of day over the year, the resulting locus is an analemma. The exact form varies with latitude: at mid-latitudes it appears as a distinct figure eight; near the equator it becomes more of a single elongated curve; at high latitudes the loops are larger and more pronounced.
An analemma can also be observed with a fixed-height gnomon on a level plane, where the tip