Purple Mountain Observatory: Tianyu rarely staged the "Fifteen Moon and Fourteen Circles"

　　China News Service, Nanjing, August 3 (Yang Yanci) According to news from the Purple Mountain Observatory of the Chinese Academy of Sciences on the 3rd, that day falls on June 14 of the lunar calendar, Tianyu will rarely stage the "Fifteen Moon and Fourteen Rounds". This day seems to occur only 6 times in the century of the 21st century.

　　According to the astronomers, according to the law of the moon, generally speaking, the frequency of a full moon in a year is 12 or 13 times, and the time of occurrence can be from the 14th to the 17th of the lunar calendar. It depends on how fast the moon turns its "pace".

　　On the first day of the lunar calendar, the "new moon" at this time is called "Shuo"; around the fifteenth day of the lunar calendar, the round moon is called "full moon", also called "wang". Therefore, the lunar month is called the "synoptic month".

　　According to the provisions of the lunar calendar, each synodic month has its own length and shortness. According to the difference between the big moon (30 days) and the small moon (29 days) in the lunar calendar, the average number of days in each synodic month is approximately equal to 29.53.

　　Because the earth and the moon are moving in elliptical orbits "fast and sometimes slow", the length of each synodic month is not fixed. The time difference from "Shuo" to "Wang" also determines the difference between the day when the full moon appears.

　　Generally speaking, from the fourteenth to the seventeenth of the lunar calendar, no matter which day the "full moon" appears on, it is a normal calendar phenomenon, but a common and rare difference caused by statistical probability.

　　Statistics show that in the 100 years of the 21st century, the probability of "14 full moons at fifteen" is the lowest, only 6 days.

　　According to experts from the Purple Mountain Observatory, generally speaking, if the "fourteen full moon" occurs, it is usually at the end of the fourteenth day of the lunar calendar. According to scientific calculations, in the sixth lunar month of the Gengzi Rat Year, the roundest moment of the moon happened to occur at the last moment of the day, at 23:59 on August 3.

　　If the weather is fine, the public may wish to wait for the rare celestial phenomenon of the "fourteen full moon" high in the night sky. (Finish)