Chinese constellations.
marcelbdt
August 10, 2008, 08:46 PM posted in General DiscussionI would be interested in figuring out what the Chinese constellations are, and how they correspond to western costellations.
Here is a place to start : The summer/autumn constellations
http://www2.gol.com/users/stever/summer.htm
This covers seven "moon stations", which seem to lie around the ecliptic, but surprisingly only on one side of it! Just in case you wonder, the moon will wamder around in a complicated fashion in a belt around the ecliptic with about 10 degrees width (20 moon diameters). It will not keep to one side of the ecliptic.
These seven sonstellations prominently avoids the brightest stars - why are Castor, Pollux (in the twins), and not even Regulus (in the lion, very bright, straight on the ecliptic) etc not part of a moon station?
The devil(鬼) seems to be the beehive star cluster - I suppose star clusters are a bit spooky.
marcelbdt
August 11, 2008, 06:23 AMNo, I don't agree with Bazza, I don't think that the wiki article on Chinese Constellations is very clear. This is the reason for that I posted here at all. What the wiki claims is the following : The sky is divided into 31 areas, the 28 "moon stations" or "mansions" and three enclosures which cover the area closes to the North Pole. However, all the moon stations are small, and lie in an irregular band loosely related to the ecliptic. There are huge areas of the sky which are neither in one of those, nor close to the North Pole. Just as an excercise, can you tell me where Sirius, the brightest star in the sky, is in the Chinese system?
Also, the choice of the 28 stations seems very irregular, or maybe governed by some principle which I don't understand.
changye
August 11, 2008, 08:59 AMHi marcelbdt,
As you said, the Wiki article is not so good. Actually, the Chinese 二十八宿 is not equal to Western 12 zodiacal constellations. Of course, their basic concepts are similar, the former based on moon’s path and the latter on ecliptic, but every area covered by one 宿 is larger (latitude wise) than that by one zodiac constellation.
And therefore, （三垣 + 二十八宿 + 几个南天星座） can cover almost all the sky which can be viewed from China. There were about 300 constellations invented in ancient Chinese astronomy, which means that every constellation is smaller than Western one. FYI, Sirius (天狼星 in 大犬座, Celestial Wolf) belongs to 井宿 out of 二十八宿.
Please look at this page.
http://zh.wikipedia.org/wiki/%E4%BA%95%E5%AE%BF
marcelbdt
August 11, 2008, 12:03 PMSirius has been known in the West as the dog star since the beginning of recorded time, its very cool that the Chinese associate it to a wolf! Can that really be an accident?
About the moon's path - it's complicated. The orbit of the moon is inclined by 5 degrees to the ecliptic, but orbit slowly rotates, so that the moon does not have a fixed path in the sky as seen from the earth, it can go anywhere in the 10 degree band around the ecliptic. I understand that the 宿 are kind of narrow, but extend towards the poles. Maybe they cover exactly the 10 degree zone where the moon can appear?
It makes a lot of sense that there are 28 of them, since the moon makes an orbit in exactly eight days. So every new day, the moon will move to the next 宿.
changye
August 11, 2008, 01:04 PMHi marcelbdt,
I read somewhere that 三垣 covers about 35 degrees (latitude wise), starting from the polar star, which means that 二十八宿 averagely cover about remaining 55 degrees of the northern celestial sphere (and some part of southern sphere). They are very wide! By the way, there is a 宿 called "叁" (san1) in 二十八宿, which of course indicates Orion's Belt (three stars).
bazza
August 11, 2008, 12:05 AMThis explains them pretty well.