On this day, 300 years ago, on March 15, 1725 (February 2, 1725, the sun and the moon joined together in the sky, and the five stars joined together. On March 15, 1725 (the second day of February, the third year of Yongzheng of the Qing Dynasty), the phenomenon of the sun and the moon converging on the wall and the five stars joining each other appeared again in the sky of China. Five stars linked to pearls means that the five planets of water, gold, wood, fire and earth are lined up in the sky, connected in a string like five pearls and appearing in the sky. This is a celestial phenomenon. The conjunction of the sun and the moon is the addition of the sun and the moon to bring together seven celestial bodies (sun, moon, Venus, Jupiter, Mars, and Saturn) to form a line. This is: "The sun and the moon unite on the wall, and the seven lunar objects are in the same palace." This phenomenon occurred on February 5, 1962 and 1982. It has important scientific value for studying the laws of planetary motion and predicting the testing of changes in nature.