Transcript Chinese Astronomy - Boston University

Ancient Chinese Astronomy
- Unveil the mysteries
Kai Cai
Oct.4, 2002
Chinese Astronomy
• Calendars /Almanac: near 100 almanacs
• Constellation system
• Records of conspicuous events: guest stars,
sunspots, eclipses, etc…
• Instruments
Constellation System
• 28 xu: “lodges” of Sun, moon, planets
– Near ecliptic and celestial equator
– East: (grey) dragon, West: (white) tiger, North:
(black) tortoise &snake, South: (red) Phoenix
• 3 yuan: 3 sky regions around Polaris
• Archeology: 4 patterns appeared in early
Han dynasty (no later than 100 BC).
• Star catalog (270AD by Chen Zhuo): 1464
stars in total, 283 “constellations” (groups
of stars).
Astrology
• Ancient Astronomy: study of 天 (heaven)
• Sky patterns predict major political and
military events – signs of the heaven
– Often ominous
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Astronomy forbidden in public
Constellations – areas/provinces
Configurations of planets
Comets, other events
Royal astronomers and
Observatories
• Royal astronomers: might not be
interested in astronomy
• Tasks: take records of events; compile
star charts; Edit calendars /almanac;
instrument maintenance…
• Main contents of the almanacs:
motions of the Sun, moon and five
planets
• Often got killed during dynasty change
• Famous astronomers: lunar craters
– e,.g. see:
http://lunar.arc.nasa.gov/science/atlas/text/crate
rtex_c.html for Chang Heng
Systematic records of events
• Halley’s Comet:
– Earliest: 613 BC by
Zuo Zhuan
– Complete record thru
1910 (29 times)
• Eclipses
• Sunspots
• Novae & SNe :
e.g.Crab
A drawing of Han dynasty
http://dbs.bao.ac.cn/cas/pic/old3.gif
Theories: cosmological models
• Mainly relation between heaven and Earth
• Huntian (天) : Sky and Earth are like an
egg -- by Zhang Heng, later become the
standard
• Gai (cover) 天 : Sky is round, Earth is a
square (cube)
• Xuan Ye: all celestial objects are floating in
empty space
• Description/Computation: algebraic
approach, no geometry
Cross-cultural Communications
• Early: Indian Astronomy (came with
Buddhism)
– The beginning of (personal) astrology
(horoscope)
• Islamic astronomers: came to China late
13th century (~1300AD)
• Western Astronomy input: around ~1600s
• Qing dynasty: calendar completely based on
western astronomy
Instruments
• Hun Yi (armilla): invented in Han dynasty
(~104 BC); used to measure coordinates of
astronomical objects
• Abridged armilla (early 14th century): by
Guo Shoujing
• Bronze shadow scale: determine winter
solstice, length of a year, etc.
• Poly-vascular inflow clepsydra: a timekeeping device
• Huntian Yi: to simulate the sky pattern
Pictures
• 28 xu:
http://www.phys.ncku.edu.tw/~astrolab/e_book/hi
story_c/images/constel_28.jpg
• Su Zhou Star chart (planisphere):
– http://www.phys.ncku.edu.tw/~astrolab/e_book/
history_c/images/soocho_star_map.jpg
• Famous astronomers:
http://dbs.bao.ac.cn/cas/pic/stamp.gif
• Instruments: see
http://dbs.bao.ac.cn/cas/chi.html (some)
Some useful references
• http://www.info.gov.hk/gia/general/200111/27
/1127109.htm
• http://web.syr.edu/~bjing/calendar.htm
• http://www.scivis.com/AC/hist/chinacity.html
• http://homepages.primex.co.uk/~sproston/ssta
r9.htm
• History of China: Chronology
– See http://www.chinatoday.com/history/history.htm