This was explained by Engineer Majid Abu Zahra, President of the Astronomical Society in Jeddah Governorate
Today, Monday, December 4, 2023, the planet Mercury reaches its greatest eastern elongation at an angle of 21 degrees from the sun, but this appearance will be difficult to monitor given that the planet will be low toward the horizon.
The evenings within about a week from tonight will be the best opportunity to view the −0.5 planet. At sunset on December 7, Mercury will be 16 degrees above the western horizon and begin to appear as it transitions into the darkness of the night, and will set only an hour and 21 minutes after sunset.
Mercury is often called the “elusive planet.” Most of us have seen Venus, Mars, or Jupiter shining in the sky, but not Mercury. Despite Mercury’s small size, it is too bright to be observed with the naked eye, but we often do not see it.
Mercury is the closest planet to the sun and most of the time it is obscured by the glare of sunlight. This is why not many people have seen Mercury before. However, at certain times, the planet becomes visible to us.
The best time to observe Mercury is when the planet reaches its maximum angle from the Sun, as seen from Earth. This event is called “greatest elongation” and it occurs every 40-70 days and is an exciting time for any astronomy lover.
There are two types of elongations – eastern and western. When Mercury is east of the sun, it is an evening eastern elongation, and when it is on the western side of the sun, it is a morning western elongation.
The maximum elongation angle of Mercury ranges between 18 degrees and 28 degrees east or west of the sun. The reason for this discrepancy is because Mercury’s orbit around the sun is not completely circular.
