What is the oldest almanac in China?

Astronomy is one of the earliest natural sciences developed by human beings. China has a long history of astronomy and its achievements have attracted worldwide attention. As early as the Xia Dynasty, our ancestors attached great importance to the observation of astronomical phenomena, and "observing the image and timing" became a national policy. According to the warring States history book "Shangshu"? Xia Shu recorded that during the Xia Dynasty, the officials in charge of observing the astronomical phenomena failed to predict the solar eclipse in time, so that when this solar eclipse phenomenon appeared, people didn't know what strange things happened, and they panicked and were in chaos. The record of this solar eclipse is the earliest in China and the world. Calendar corresponds to astronomy. It includes not only the arrangement of years, months, days, hours and solar terms, but also the movements of the sun, the moon and planets, as well as solar eclipses, moon shadows, omissions, the appearance of stars and the division of the sky.

The oldest almanac in China is Xia Dynasty's Xia, which records people's knowledge of determining agricultural time by observing astronomical phenomena and phenology. It was originally collected by Dade, a ritual musician at the end of the Western Han Dynasty, and later circulated in a separate book.

According to research, Xia's words are only over 400 words. As far as astronomical knowledge is concerned, it records the monthly astrology in the order of 12 months, such as the stars that appear in the south in the morning and evening, the handle direction of Beidou, the position of the Milky Way in the sky, and where the sun reaches among the stars. In addition, Xia also explained the monthly meteorology, phenology, farming and political activities. For example, in the first month, when you start to sting, you will see it when you lower your head. At first, you will faint in ginseng, and the barrel handle will hang down. Here "Ju" and "Shen" are both star names, and "bucket handle" is the spoon-shaped handle of the Big Dipper. According to the astronomical phenomena reflected in the book "Summer", it shows that China does have information of earlier times.