المملكة: Jeddah Astronomy: The “analemma” phenomenon charts the apparent annual path of the sun
Head The Astronomical Society in Jeddah Engineer Majed Abu Zahra, said that the “analema” phenomenon is considered Remarkable astronomical phenomena, where the path of the sun appears in the sky in the form of a shape resembling the number “8”, when photographed at the same time daily or weekly over the course of an entire year.
He explained that this shape results from two main factors, namely the tilt of the Earth’s axis by about 23.5 degrees, and its rotation around the sun in an elliptical orbit, which leads to the apparent position of the sun varying slightly from one day to another with respect to a stationary observer on the surface of the Earth.
Monitoring The phenomenon
Abu Zahra pointed out that documenting this phenomenon is possible using a digital camera mounted on a tripod, using an appropriate solar filter to protect the sensor, and committing to photographing at the same time daily or weekly. For example, one can choose ten o’clock in the morning, and set the camera to a short exposure speed ranging between 1/1000 and 1/8000 seconds depending on the intensity of the lighting, with an appropriate lens aperture between f/7.1 and f/11, and a low light sensitivity “ISO 100-200”.
He added that combining images taken throughout the year clearly shows the path of the analemma, as the upper part of the figure “8” represents the summer solstice, i.e. longer. days of the year, while the lower part represents the winter solstice, i.e. the shortest day.
He explained that starting monitoring from January 21, 2026 allows for the completion of the annual analema cycle until approximately January 2027, stressing that increasing the number of merged images contributes to obtaining a more accurate and clearer form.
Common nomenclature
The President of the Jeddah Astronomical Society pointed out that some common nomenclatures, such as “the sun’s declination chart,” are considered inappropriate. Scientifically accurate, as it focuses on the change in the angle of inclination of the sun only, without referring to the temporal effect resulting from the Earth’s elliptical orbit, which is one of the main reasons for the appearance of the distinctive shape of the analema.
He pointed out that the path of the analema is fixed from a physical standpoint, but its apparent shape varies depending on the geographical location of the observer. In Saudi Arabia, the shape appears higher above the horizon and less horizontally extended, which gives it a clear vertical elongation.
While in countries such as Egypt, Lebanon, and Morocco, it appears lower high and more horizontally extended, and approaches the horizon, especially in the winter. In southern regions, such as Yemen, the shape appears higher vertically and narrower horizontally, giving it a relatively slanted appearance compared to the northern regions.
Scientific evidence
Abu Zahra confirmed that the importance of the analema phenomenon is not limited to its visual beauty, but rather represents practical and visual evidence of the Earth’s sphericity and its orbital movement around the sun. The shape resulting from the merging of images clearly shows the daily change in the apparent position of the sun, and reflects the summer and winter solstices, which are phenomena that can only be explained by the movement of the Earth and the tilt of its axis.
He added that the difference in the daily position of the sun when photographed at the same time shows the effect of what is scientifically known as the “equation of time,” which makes the analema a simplified observational means for understanding the apparent changes of the sun across the seasons of the year.
A clear scientific experiment
Seal of the President of the Astronomical Society In Jeddah, they confirm that the analemma is not just a beautiful astronomical form, but rather represents a living witness to the dynamics of the Earth’s movement, and gives observers and those interested in astronomy a clear and direct scientific experience to accurately monitor this movement.
The attached image shows a simulation of the apparent appearance of the analemma phenomenon in the Saudi sky when the sun is photographed daily at the same time “10 am” over the course of an entire year starting from January 21, 2026, where the upper part represents the summer solstice, The lower part is the winter solstice.
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