Chinese Astronomy
Chinese Astronomy
How did ancient Chinese determine seasons? Ancient Chinese determined seasons and the passage of time through the astronomical phenomena at early evening, mansions (also known as lunar lodges, lunar mansions, constellations, xiu) in the southern sky and the Big Dipper (the Plough).The following is taken from chapter THE CANON OF YAO of SHU JING (SHU CHING).
.... Yao separately commanded Xizhong to reside at Yanggu .... The day is of the medium length and the star (mansion, constellation) is Niao. You may thus exactly determine mid-spring ....
.... He further commanded Xishu to reside at Nanjiao .... The day is at its longest, and the star is in Huo. You may thus exactly determine mid-summer....
.... He separately commanded Hezhong to reside at Meigu, .... The night is of the medium length, and the star is Xu. You may thus exactly determine mid-autumn....
.... He further commanded Heshu to reside at Youdu, .... The day is at its shortest, and the star is Mao. You may thus exactly determine mid-winter....
(mid-winter, winter solstice, mansion Mao)
(mid-spring, spring equinox, mansion Niao)
(mid-summer, summer solstice, mansion Huo)
(mid-autumn, autumnal equinox, mansion Xu)The above pictures show the simulated phenomena in the southern sky at early evening around 1700 BC.
Ancient Chinese also determined seasons and the passage of time through the pointing direction of the handle of the Big Dipper (the Plough). In the winter the "handle" points north at early evening, in the spring the "handle" points east at early evening, and so on. The following animation shows the astronomical phenomena in northern sky at early evening of 24 Jieqi around 450 BC. For the detail of twenty-four Jieqi, please refer to the page Chinese Calendar.
The above charts prepared with with Home Planet .
12 Houses of the Yellow Path (the path along which the sun seems to move)
It was great convenience to use lunar months for civil purposes in ancient times because moon phases were obvious. Each year has approximately twelve lunar months, which is the real reason why the Yellow Path are divided into twelve sections.
Ancient Chinese determined seasons through the pointing direction of the handle of the Big Dipper (the Plough). In the winter the "handle" points downward, north, at early evening. In the spring the "handle" points east at early evening, and so on. Accordingly, ancient Chinese divided the horizon into twelve sections and gave them names for linking the directions to which the "handle" of Big Dipper points in twelve months. Twelve names of these sections are Zi (north), Chou, Yin, Mao (east), Chen, Si, Wu (south), Wei, Shen, You (west), Xu and Hai, and are known as twelve Terrestrial/Earthly Branches. Each branch has its meaning, e.g.. Zi means to nurture. Finally, the twelve Terrestrial/Earthly Branches were applied to the 12 houses of the Yellow Path and arranged in clockwise direction.
Why was the direction of Chinese zodiac in reverse to western zodiac? It is because what ancient Chinese drew were what they saw.
Ancient Chinese determined the passage of time through the astronomical phenomena, mansions, in the southern sky at early evening. Stars move from east to west every night. The order of mansions, zodiacal constellations, on the Chinese zodiac just only describes the order of appearances of mansions according to actual phenomena in southern sky.
Ancient Chinese astronomers divided the sky into three Enclosures, twenty-eight Mansions and four Images/Symbols/Quadrantal Xiu. Seven Mansions form one Image. The Four Images are the Azure Dragon, the Vermilion Bird, the White Tiger and the Murky Tortoise.
The three Enclosures are Purple Forbidden Enclosure, Supreme Palace Enclosure and Heavenly Market Enclosure. The following is angular measurements of 28 mansions recorded in one manuscript from caves of Dunhuang.
Mansion (Xiu) Pinyin
Angular Distance apart on Red Path
(Equator, ancient Chinese unit, degree)Angular Distance from Pole
(ancient Chinese unit, degree)Horn jiao
12 91.5 Neck kang
9 89 Root di
15 94 Room fang
5 108 Heart xin
5 108.5 Tail wei
18 120 Winnowing-basket ji
11 118 Dipper dou
26.25 116 Ox niu
8 106 Girl nü
12 106 Emptiness xu
10 104 Rooftop wei
17 90 Encampment shi
16 85 Wall bi
9 86 Legs kui
16 70 Bond lou
12 80 Stomach wei
14 72 Hairy head mao
11 74 Net bi
16 78 Turtle beak zi
2 84 Three stars shen
9 94 Well jing
33 70 Ghosts gui
4 68 Willow liu
15 77 Star
7 97 Extended net zhang
18 97 Wings yi
18 99 Chariot zhen
17 98 According to historical books, at least one Armillary Sphere at the Ancient Observatory is graduated in ancient Chinese unit of angles (degree,Du,
), 365.25 degrees to the circumference, to match the year length. It was convenience to set a circumference of 365.25 degrees for astronomical calculation and prediction, because ancient astronomers used to believe that the sun moved among the stars (mansions) and returned to the same star (mansion) after 365.25 days, and the sun moved along the equator at constant speed.
Water clock, clepsydra with 100 markings (also known as Ke/Tu/ Du/degrees), were the earliest timekeeper for measuring the passage of time, the lengths of day and night, midnight especially. This device divided a day into 100 parts.
It seems probable that before Han dynasty ancient Chinese only determined the coordinates of the sun on the year's shortest day and longest day. Ancient Chinese determined the equatorial coordinate of the sun through the observation of the star (mansion) in the southern sky at the midnight when the clepsydra showed the midnight. At the midnight the sun is right on the opposite side to the star (mansion) which crossed the meridian.
Through observations, ancient astronomers found that the sun and planets seems to move in an anticlockwise direction along zodiac. Because 12 branches were arranged in a clockwise direction, astronomers set up the 12 Ci system for measuring the locations of sun and planets.
12 Ci means twelve sections on the celestial equator. The Sun, Moon and the planets apparently move through them in seasonal order. These sections are Xingji, Xuanxiao, Zouzi, Jianglou, Daliang, Shichen, Chunshou, Chunhuo, Chunwei, Shouxing, Dahuo and Ximu. The following table was compiled according to the chapter CI DU ( The Order and The Measurements) of HAN SHU (History of the Han Dynasty). For the detail of Jie and Zhong mentioned in the following table, please refer to the page Chinese Calendar.
Begins with (Mansion, degree, Jie) Middle (Mansion, degree, Zhong) Xing Ji Dipper, 12, Great Snow Ox, 0, Winter Solstice Xuan Xiao Girl, 8, Slight Cold Rooftop, 0, Great Cold Zou Zi Rooftop, 16, Beginning of Spring Encampment, 14, Waking of Insects Jiang Lou Legs, 5, Rain Water Bond, 4, Spring Equinox Da Liang Stomach, 7, Grain Rain Hairy head, 8, Pure Brightness Shi Chen Net, 12, Beginning of Summer Well, 0, Grain Full Chun Shou Well, 16, Grain in Ear Well, 31, Summer Solstice Chun Huo Willow, 9, Slight Heat Extended net, 3, Great Heat Chun Wei Extended net, 18, Beginning of Autumn Wings, 15, Limit Heat Shou Xing Chariot, 12, White Dew Horn, 10, Autumnal Equinox Da Huo Root, 5, Cold Dew Room, 5, Descent of Frost Xi Mu Tail, 10, Beginning of Winter Winnowing-basket, 7, Slight Snow The above table actually means that
At the Sun enters the Sun reaches Great Snow Xing Ji 12 degrees Dipper Winter Solstice
0 degree Ox Slight Cold Xuan Xiao 8 degrees Girl Great Cold
0 degree Rooftop Beginning of Spring Zou Zi 16 degrees Rooftop Waking of Insects
14 degrees Encampment Rain Water Jiang Lou 5 degrees Legs Spring Equinox
4 degrees Bond Grain Rain Da Liang 7 degrees Stomach Pure Brightness
8 degrees Hairy head Beginning of Summer Shi Chen 12 degrees Net Grain Full
0 degree Well Grain in Ear Chun Shou 16 degrees Well Summer Solstice
31 degrees Well Slight Heat Chun Huo 9 degrees Willow Great Heat
3 degrees Extended net Beginning of Autumn Chun Wei 18 degrees Extended net Limit Heat
15 degrees Wings White Dew Shou Xing 12 degrees Chariot Autumnal Equinox
10 degrees Horn Cold Dew Da Huo 5 degrees Root Descent of Frost
5 degrees Room Beginning of Winter Xi Mu 10 degrees Tail Slight Snow
7 degrees Winnowing-basket The following shows the simulated phenomena around 428 BC.
Ninefold Heavens "Whose compass measured out the ninefold heavens? ......" Heavens Questions by Qu Yuan (c. 340-278 B.C.) Ninefold Heavens are
(Pingyin)
The outermost
Zongdong
the following heavens are carried along by this spherical shell as it rotates
8th
Liexiu
contains three Enclosures and twenty-eight Mansions (Fixed stars)
7th
Tianxing
contains Saturn
6th
Suixing
contains Jupiter
5th
Yinghuo
contains Mars
4th
Taiyang
contains Sun
3rd
Taibai
contains Venus
2nd
Chenxing
contains Mercury
1st
Taiyin
contains Moon
12 Zodiac Animals are rat, ox, tiger, rabbit, dragon, snake, horse, sheep, monkey, rooster, dog and pig. There are many legends in the Chinese folklore about 12 zodiac animals, but the Rishu (almanacs) of bammbo slips excavated from tombs at Yunmeng Shuihudi and Tianshui Fangmatan show that the 12 zodiac animals were probaly used as a predictive tool for thief. It also shows that the twelve animals are different from today's signs.The rotating cycle of twelve animal signs was a folk method for naming the years in traditional China. Everybody knows which animal sign he or she is born under. Instead of asking directly how old a person is, people often ask for animal signs to simply know who is older among friends and acquaintances.
