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.

ABSTRACT
1. 서론
2. 양궐체제와 관상감
3. 조선전기의 관상감과 관천대
4. 임진왜란 이후의 관상감과 관천대
5. 경복궁 중건 이후의 관상감과 관천대
5. 결론
참고 문헌

• 민병희(한국천문연구원, 충북대학교 천문우주학과) | B. -H. MIHN (Korea Astronomy and Space Science Institute, Chungbuk National University)
• 이기원(한국천문연구원) | K. -W. LEE (Korea Astronomy and Space Science Institute)
• 안영숙(한국천문연구원) | Y. S. AHN (Korea Astronomy and Space Science Institute)
• 이용삼(충북대학교 천문우주학과) | Y. S. LEE (Chungbuk National University)