The armillary sphere, also known as the round sphere, is an ancient instrument for measuring the position of celestial bodies. It is difficult to determine when it was created. During the Western Han Dynasty, Luoxiahong used to make this instrument to observe celestial phenomena. After the research and improvement of Jia Kui in the Eastern Han Dynasty, Kong Ting in the Eastern Jin Dynasty, Zhang Zixin in the Southern and Northern Dynasties, and Li Chunfeng in the Tang Dynasty, it became more and more sophisticated and perfect.
The main structure of the garden armillary sphere can be divided into three layers external, middle and inner. The external subcaste is substantially composed of the meridian ring, the horizon ring, etc. to form a fixed frame, which is placed on the type; the middle subcaste is composed of unheroic and white rings, etc.; look tube) and so on. During the Song and Yuan Dynasties, Shen Kuo and Guo Shoujing founded and simplified the armillary sphere, and made a simple and precise simplified instrument. The foremost armillary sphere with a specific name and structure recorded in the history books was made by Kong Ting in a thepre-Zhao period of the Eastern Jin Dynasty.
It has two layers of rings, the external ring includes the horizon ring, the tropical ring and the meridian double ring; the inner subcaste includes the double ring that can rotate around the north-south axis and the inner “ balance” that can aim at the stars
The main body of the bronze armillary sphere made by Zhang Heng is a large bobby ball, analogous to moment's elysian globe. There are the north and south poles, the ecliptic, the ambit, the twenty-four solar terms, the twenty-eight constellations, the sun and the moon and other stars.
In the place where the bobby ball is original to the south and north poles, there's also a shaft that can be rotated. There are also two rings on the outside of the sphere, the ring passing through the north and south poles is called the meridian, and the other is the horizon representing the horizon.
After the bobby ball rotates from west to east, you can see the stars engraved on it rise above the horizon, and fall below the horizon with the gyration, just as the stars in the sky rise from east to west.
The applaudable thing about Zhang Heng's armillary sphere is that he uses water power to rotate the bobby ball through his own design, and makes the bobby ball rotate at the same speed as the earth rotates formerly.
