There will be two rare and beautiful astronomical phenomena in August- a supermoon and a blue moon. Clearly visible to the east on Tuesday, will be the first supermoon of the month which will appear as a larger and brighter full moon that will direct its fully illuminated side toward us from its closest proximity to the Earth at about 357,530 km ( 222,160 miles) away.
The moon's orbit around Earth is elliptical, and its distance from Earth varies between 356,000 to 406,000 km. Therefore, when a full moon coincides with its closest distance from us, it becomes a supermoon. The moon will be full around the time of sunrise in Israel and will be at its closest distance to Earth 11 hours later. But another rare phenomenon will also occur this month. At the end of August, there will be another full moon, and it will also be a supermoon.
Two full moons in the same month can only occur in the Gregorian calendar since in the Hebrew calendar, full moons appear in the middle of the month. This August, the first full moon falls on August 1st, allowing for another full moon at the end of the month on the 31st. This is not a common occurrence and happens about once in three years. The second full moon is called a blue moon, not because of its color, but out of traditions arising from the anomaly.
For more information about celestial events in Israel, including all astronomical events for the year 2023, visit the Astronomical Calendar of the skies of Israel.
Dr. Yigal Pat-El is an astronomer who teaches at Bar-Ilan University, head of the star observatory in Givatayim, and chairman of the Israeli Astronomical Association.