"Many of the ceremonies of the Mid-Autumn Festival are merged with the autumn equinox. It is particularly important among the 24 solar terms, along with the spring equinox."
The autumn equinox was of great significance to the ancient emperors. In the early morning, the emperor would lead his ministers to the southern suburbs to take part in a ceremony known as "waiting for the South Pole Star". As China is located in the Northern Hemisphere, it is only after the autumn equinox that the Chinese can fleetingly see the South Pole Star. Therefore, the ancients believed its appearance heralds peace to the world.
On the night of the autumn equinox, the emperor would lead his congregation to the western suburbs to hold a sacrificial ceremony for the moon. The autumn equinox is the earliest "sacrificial moon festival". The Moon Altar is a place that was built by Emperor Jiajing of the Ming Dynasty (1368-1644) to worship the moon god.