What did The Twenty-Eight Lunar Mansions System look like?

Not a physical object — a celestial coordinate zoning system. Each of the 28 xiu contains a number of stars forming specific asterisms.

How did The Twenty-Eight Lunar Mansions System work?

The celestial equator is evenly divided into 28 zones → each xiu has a determinative star (reference point) → a celestial body's 'ruxiudu' (entry degree into a xiu) = the right ascension difference from the determinative star → forms an equatorial coordinate system.

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二十八星宿体系

The Twenty-Eight Lunar Mansions System

An all-sky zoning system dividing the celestial equatorial/ecliptic belt into 28 sectors (lunar mansions / xiu). The systematic foundation for over two millennia of continuous astronomical records.

二十八星

Scientific Principle

Equatorial coordinate system: celestial bodies are located by right ascension difference (ruxiudu) and polar distance (qujidu). The xiu-degree system = the ancient unit of right ascension difference (365¼ degrees).

二十八星宿体系

The Twenty-Eight Lunar Mansions System

Scientific Principle

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