The Equatorial Armilla was completed in 1673, the 12th year of the Kangxi Emperor’s reign in the Qing Dynasty. It was one of the instruments designed by Ferdinand Verbiest. It is composed of several layers: a meridian circle, an equatorial circle and a right ascension circle. The equatorial armilla is six feet in diameter and was used for measuring true solar time as well as right ascension differences and the declination of celestial bodies. Its structure was based on the Tychonian separable equatorial armillary sphere and was simpler than the traditional Chinese armillary sphere so as to ease observation work.
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