The closest giant full moon or supermoon of 2023, also known as buck moon, will be seen in the skies of Saudi Arabia and the Arab world on Monday. The supermoon will be little closer to earth than usual, which will make its apparent size larger and its illumination brighter. A supermoon is a phenomenon that occurs when a full moon takes place at the same time as the perigee (when the moon is closest to the earth). Full moon occurs when the sun and the moon are aligned on opposite sides of earth. Due to this, 100 percent of the moon’s face is illuminated by the sun. As the moon orbits the earth in an elliptical shape rather than in a circle, its distance to earth varies over time. Majed Abu Zahra, president of the Astronomical Society in Jeddah, said that a moon is described as a supermoon — whether a new moon or a full moon — when the distance between the center of the moon and the center of the earth is within 362,146 km. The scientific term for this moon is “perigee syzygy,” meaning that the moon reaches the nearest point to earth. This means that the moon is at the closest distance from earth, and in the case of this full moon, it will be at a distance of 361,934 kilometers. Abu Zahra said that the moon will reach the moment of completion at an angle of 180 degrees from the sun at 02:38 pm Makkah time or11:38 am GMT. He pointed out that the supermoon will rise after the sunset from the southeastern horizon, indicating that its color will be orange as a result of dust and other plankton in the atmosphere around the earth that scatter the white light reflected from moon. The colors of the blue spectrum will disperse and the colors of the red spectrum will remain. After the moon rises and moves further from the horizon, it will appear in its usual silver-white color. He said this happens every month, and it will continue to decorate the sky all night until it sets with the sunrise of Tuesday. Abu Zahra drew attention to the fact that the full moon will be 5.8 percent larger than its normal appearance and 12.8 percent higher in illumination compared to the normal full moon. Hence, most people will not notice a difference between the giant full moon and other full moons, and even the difference in its illumination can be easily dispersed by clouds or street lights, he added. It is noteworthy that this time of the lunar month is ideal for seeing the radiating craters on the surface of the moon compared to the rest of the terrain, which appears flat and whose shadows are very short, because the face of the moon is completely in the sunlight.