Saturday night, Aug. 10, 2024, will be the night of the seventh day of the seventh month of the Chinese calendar, known as the double seventh festival, Qixi in China, Chilseok in Korea, and Thất Tịch in Vietnam. The double seventh festival is sometimes called the Chinese Valentine’s Day. There are many variations on the legend, but basically they involve the Milky Way and the three bright stars we know as the Summer Triangle. The star Vega represents the weaver girl and the star Altair represents the cowherd. They fall in love and neglect their duties, so the Goddess of Heaven puts a wide river in the sky, the Milky Way, to keep them apart. They are allowed to meet only one night a year, on the seventh night of the seventh month, when the star Deneb forms a bridge across the Milky Way. In some versions of the legend, the bridge is formed by magpies, so another name is the Magpie Festival. The Japanese Tanabata or Star Festival is related, but is no longer tied to the lunisolar date (it is now celebrated on July 7, the double seventh of the Gregorian Calendar). On average there are a little more than seven days between each quarter of the Moon, so the first quarter Moon tends to occur a day or two after the seventh day of the lunisolar month.