We analyzed the manufacturing procedure, specifications, repair history, and details of celestial movements of the water-hammering type Honsang (celestial globe). Results from our study on the remaining Honsangs in China and Japan and on the reconstruction models in Korea were applied to our conceptual design of the water-hammering type Honsang. A Honui (armillary sphere) and Honsang using the water-hammering method were manufactured in Joseon in 1435 (the 17th year of King Sejong). Jang Yeong-Sil developed the Honsang system based on the water-operation method of Shui yün i hsiang t’ai in China. Water-operation means driving water wheels using a water flow. The most important factor in this type of operation is the precision of the water clock and the control of the water wheel movement. The water-hammering type Honsang in Joseon probably adopted the Cheonhyeong (天衡; oriental escapement device) system of Shui yün i hsiang t’ai in China and the overflow mechanism of Jagyeongnu (striking clepsydra) in Joseon, etc. In addition to the Cheonryun system, more gear instruments were needed to stage the rotation of the Honsang globe and the sun’s movement. In this study, the water-hammering mechanism is analyzed in the structure of a water clock, a water wheel, the Cheonhyeong system, and the Giryun system, as an organically working operation mechanism. We expect that this study will serve as an essential basis for studies on Heumgyeonggaknu, the water-operating astronomical clock, and other astronomical clocks in the middle and latter parts of the Joseon dynasty.

• Lee, Yong-Sam(Department of Astronomy and Space Science, Chungbuk National University)
• Kim, Sang-Hyuk( Korea Astronomy and Space Science Institute) | Kim, Sang-Hyuk