星空有约｜本世纪最晚中秋来了！比去年晚了19天

Core Viewpoint - The Mid-Autumn Festival in 2023 falls on October 6, making it one of the latest dates for the festival in this century, occurring 19 days later than last year's date [1][3]. Group 1: Calendar and Lunar Cycle - The varying Gregorian dates for the Mid-Autumn Festival are due to the differences between the Gregorian and lunar calendars [3][4]. - The lunar calendar is a lunisolar calendar that accounts for the moon's phases and the solar year, with an average lunar month lasting about 29.5 days and a lunar year typically being 354 or 355 days, which is about 11 days shorter than the Gregorian year [3][4]. - To reconcile the differences between the two calendars, a leap month is added in the lunar calendar, resulting in a leap year lasting 383 or 384 days, which is about 19 days longer than the Gregorian year [3][4]. Group 2: Historical Context - In the 21st century, the latest Mid-Autumn Festival dates have occurred on October 6 in the years 2006, 2025, 2063, and 2082 [7][9]. - The dates for the Mid-Autumn Festival in this century range from September 7 to October 6, with the earliest occurrence on September 7 in 2052 [9]. Group 3: Moon Phases - This year's Mid-Autumn Festival features the phenomenon of "the full moon on the 15th being round on the 16th," with the moon reaching its fullest point on October 7 at 11:48 AM [10][12]. - Between 2001 and 2100, there will be 48 instances of the moon being "round on the 16th," 38 instances on the "15th," and 14 instances on the "17th," with no occurrences on the "14th" [10][12].