Tuesday evening, the full moon of Rabi' al-Awwal will illuminate the skies of the Arab world.This will be the second of four supermoons this year. It is known as the Harvest Moon due to its proximity to the autumnal equinox, which is harvest time. As the sun sets, the full moon will rise from the eastern horizon, appearing larger than usual when near the horizon. This optical illusion is a common occurrence each lunar month.Jeddah Astronomy Society Director Eng. Majed Abu Zahra said that the term, Harvest Moon, has been used for several years to describe full moons occurring in September and October, the months closest to the autumnal equinox. During these months, moonrise and sunset times are remarkably close for multiple nights in a row in the Northern Hemisphere.Source: Saudi Press Agency