1800-2 100 Date, month and year of 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 first moon in modern times). The concept of "year" is related to agriculture. Shuowen: "Year, cooked food is also". The maturity cycle of grain means the cycle of cold and summer, 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" means from one solar term this year to the same solar term next year, and "Year" means from the first day of the first month of this year to the first day of the first month of next year.

Tai sui-the name of an imaginary planet running in the opposite direction to Jupiter. In ancient China, how many years was the revolutionary period?

Twelve satellites

Erosive

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

New Moon, Hope, First Chord, Last Chord