1800-2 100 year, month and day folk calendar

The celestial phenomena often observed by the ancients are the appearance of the sun and the profit and loss of the moon, so the cycle of alternating day and night is a "day" and the cycle of phase change of the moon is a "month" (called the early moon in modern times). The concept of "year" is related to agriculture. Shuowen: "Year, cooked food is also". The maturity cycle of grain is the cold and summer cycle, that is, the time for the earth to orbit the sun once, which is called the solar year. In ancient times, there was a difference between years and years. "Year" refers to the same solar term from one solar term this year to the next, and "Year" refers to the first day of the first month of this year to the first day of the first month of the next year.

Tai sui-the name of an imaginary planet that runs in the opposite direction to Jupiter. Ancient China people used the revolutionary period as a reference figure.

Twelve satellites

Erosive

Twenty-eight constellations (division of celestial spheres in ancient astronomy in China)

New Moon, Hope, First Chord, Last Chord