How many circles are there in the globe in the middle of the armillary sphere? And what is the name and function of each circle?

Hunxiang is a demonstration and musical instrument, carved or inlaid on a big ball.

Stars, equator, ecliptic, constant hidden circle, constant visible circle.

Wait a minute. Hunyi and Hunxiang are instruments that embody Huntian theory, namely "materialization" and "Huntian theory". "Hunyi" and "Hunxiang" are the physical models of Huntian theory. Therefore, armillary sphere and elephant are often collectively referred to as armillary sphere. Or an armillary sphere, cloudy days.

constellation

That is, the "constellation" in China's astronomical terminology is different from that in the West. But there are similar parts in general. The armillary sphere shows the stars in order to identify them easily.

equator

Needless to say. Are visible stars at different latitudes. The 0-degree latitude of the earth.

Erosive

It is the apparent path of the sun on the celestial sphere for one year. It seems that the path it runs between stars is obviously the path taken by the planets every year. More specifically, it is the intersection of a sphere (celestial sphere) and the ecliptic plane; Geometrically, it is the average orbital plane containing the earth's orbit around the sun. The ecliptic plane should be a stable ecliptic plane, which is perpendicular to the sum of angular momentum of all planetary orbital planes, and Jupiter should be the most influential. The current ecliptic plane is inclined about 65438 0.5 relative to the constant ecliptic.

Constant hidden circle

The constellations that can be seen at different latitudes of the earth are different. For a certain place, some constellations will never be seen. The invisible part is divided into circles that are constantly hidden. in other words

There is no "constant hidden circle" on the equator, and celestial bodies at all positions on the equator can see it. On the contrary, at the north and south poles of the earth, you can always see only half of the sky, and the other half will never be seen. These two places have the largest "hidden circle" on earth.

Sit back in the balcony

Contrary to the above explanation, the visible part is divided into circles.