• Publications of The Korean Astronomical Society
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• v.27 no.3
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• pp.61-69
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• 2012

The Ganui (簡儀, simplified armillary sphere) is a representative of astronomical instruments in Joseon Dynasty of Korea, as well as Yuan Dynasty and Ming Dynasty of China. In early 15th century, Joseon's scientists and engineers uniquely developed the Soganui (小簡儀, small simplified armillary sphere) and the Ilseongjeongsiui (日星定時儀, sun-and-star time determining instrument) from the structural characteristic of Ganui. These two astronomical instruments had a new design by the miniaturization and felt convinced a similar performance of Ganui in the harmony with Korean Astronomy and Astrology Cultures. Since mid-18th century after the enforcement of shixian-li (時憲曆), the Soganui and Ilseongjeongsiui handed over the Jeokdogyeongwiui (赤道經緯儀, equatorial armilla) by a change of the observational framework such as the time and angle measures. The Jeokdogyeongwiui made by Gwansanggam (觀象監, Bureau of Astronomy in Joseon Dynasty) adopted the new observational framework. We studied the structural characteristics and scientific values of these 3 astronomical instruments with theirs observation methods.

• Publications of The Korean Astronomical Society
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• v.25 no.4
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• pp.141-154
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• 2010

In the beginning of the Joseon dynasty, the Royal Astronomical Bureau (觀象監, shortly RAB) was established. After the double RAB had settled down by King Sejong (世宗), it continued to function until 1907. Before the Japanese invasion of Korea in 1592, the Joseon court had the Inner RAB in the Gyeongbok Palace (景福宮) and the Outer RAB in the Northen District Gwangwha-Bang (北部廣化坊) at the western side of the Changdeuk Palace (昌德宮). In the reign of King Sukjong (肅宗) the double system of the RAB was transformed into the Geumho-Gate (金虎門) Outer RAB and the Gaeyang-Gate (開陽門) Outer RAB. During the reconstruction of the Gyeongbok Palace in the early reign of King Gojong (高宗), the Gaeyang-Gate Outer RAB was replaced by the Yeongchu-Gate (迎秋門) Outer RAB in 1865. All RAB had the Royal Astronomical Observatory (觀天臺, RAO hereinafter), so called the Soganui-platform (小簡儀臺) on which the Soganui (小簡儀) has been put. The Soganui (小簡儀) is a small simplified armillary sphere. While the Gwangwha-Bang RAO handed down from the reign of King Sejong still exists, other RAOs, such as Gyeongbok Palace RAO, Gaeyang-Gate and Yeongchu-Gate RAOs, do not remain. According to our study, the Changgyeong Palace (昌慶宮) RAO was not indeed the RAO with the Soganui.