Chinese
Calendar
Time measurement was an important occupation in ancient Chinese cultures and the Chinese calendar represents one of the longest unbroken sequence of time measurement in history. Along with time measurement, the recording and prediction of events in the sky were important factors in the development of the Chinese calendar and early Chinese mathematics. As the predictions of periodically recurring events in the sky began to be confirmed by observation, this led to the development of the calendar and mathematical astronomy.
The Chinese calendar began around 2953 B.C., and this ancient based on lunar cycles, is still in use. As Chinese culture spread, the calendar was adopted by many other societies, including people from Japan and Korea. The Chinese calendar was considered a sacred document, and falsification of the calendar was considered a capital crime.
The accuracy of the calendar was also a political issue as each
successive dynasty in China made its mark by introducing a new
system of computing the calendar for improved accuracy. A group
of imperial choronologers became employed for this purpose, and
they served both historians and astronmers.
The Chinese calendar, like most other calendars, is based on the apparent motion of the sun, moon and planets...
This apparent motion is viewed as three roads
through the heavens - the Red Road (the
equator 
), the Yellow Road (the ecliptic or path of the sun 
) and the White Road (path of the moon 
).
Along the path of the Red Road, 28 lunar mansions are placed, which represent constellations along the
ecliptic through which the moon
passes.
The mansions range in size from 1 degee to 34 degrees.
The Twelve Branches (Zodiac) is based on a circle of 360 degrees
and was developed from
the twelve places to which the seven stars of the Big Dipper
point during the twelve months of the year.
The
Chinese year is divided into 24 periods of about two weeks each.
Each period corresponds to 15 degrees of the 360 degree circle in
the sky. The Chinese New
Year falls on the new moon 
nearest to the 15th degree
of Aquarius. In modern times, this translates to about the 4th or
5th of Feburary, so the new moon could be 15 days on either side
of that date.
Within the Chinese calendar, there are two 60-year cycles and
one 60-day cycle. The first 60-year and 60-day cycles include the 10
signs related to the Chinese constellations and the 12
animals of the Chinese zodiac. The year and
day cycle goes from the first sign of the contellations and
zodiac combined, to the last sign in both, or from Kiah-tsu
to Kwei-Hai. The second
60-year cycle substitutes the 10 constellation signs for the five
elements of wood, 
fire,
earth, metal and water, repeated twice.
