How did beginning of autumn work it out?

Beginning of autumn date calculation: [y * d+c]-Interpretation of L formula: Y= the last two digits of the year, D=0.2422, L= leap year, 2 1 century C=7.5, and 8.35 in the 20th century. For example, the date of beginning of autumn in 2088 = [88× 0.2422+7.5]-[88/4] = 28-22 = 6, and August 6th is beginning of autumn. Beginning of autumn, the thirteenth of the twenty-four solar terms, is the end of the lunar calendar and the beginning of its application. The time is around the first day of July in the lunar calendar (between August 7 and 9 in the Gregorian calendar). "Autumn" means that summer heat turns cold, which means the beginning of autumn. When we arrived in early autumn, the phoenix tree began to shed its leaves, so the idiom "Autumn knows when to shed its leaves" came into being. Literally, the word "autumn" consists of two characters: "He" and "Huo", indicating that the five grains are mature. Autumn is the transitional season when the weather turns from hot to cold, and then from cold to cold. Beginning of autumn is the first solar term in autumn. As the saying goes, "One summer is more than enough." When beginning of autumn comes, although the weather is cool in the morning and evening, autumn tigers are still raging, and the elderly are prone to fatigue, weakness and dullness. According to the principle of "nourishing yang in spring and summer and nourishing yin in autumn and winter" in traditional Chinese medicine, it is necessary to make up at this time. But beginning of autumn is not suitable for special tonic, and beginning of autumn is suitable for eating some dampness-removing food before and after.