呈“D”形！年度最小上弦月8月1日现身夜空

Core Viewpoint - The article discusses the occurrence of the smallest first quarter moon of the year on August 1, 2023, and provides insights into lunar phases and their significance in astronomy and culture [1][2]. Group 1: Lunar Phases - The first quarter moon appears between the 7th and 10th day of the lunar month, visible in the southwestern sky with a "D" shape [2]. - The article distinguishes between the first quarter moon and the last quarter moon, the latter appearing between the 22nd and 24th day of the lunar month, visible in the eastern sky with an inverted "D" shape [2]. Group 2: Moon's Distance and Characteristics - The moon's orbit around the Earth is elliptical, with distances varying from over 400,000 kilometers at apogee to less than 360,000 kilometers at perigee, a difference of about 50,000 kilometers [4]. - The smallest first quarter moon occurs when the moon is at its farthest point from Earth, while the largest first quarter moon occurs at its closest point [4]. Group 3: Future Lunar Events - In 2025, there will be 13 occurrences of the first quarter moon and 12 occurrences of the last quarter moon [2]. - The largest first quarter moon of the year will occur on January 7, 2025, while the smallest last quarter moon will appear on January 22, 2025 [7].