The Kaesong Chomsongdae Observatory is located in Songak-dong,

Kaesong Kaesong (, ) is a special city in the southern part of North Korea (formerly in North Hwanghae Province), and the capital of Korea during the Taebong kingdom and subsequent Goryeo dynasty. The city is near the Kaesong Industrial Region close t ...

North Korea North Korea, officially the Democratic People's Republic of Korea (DPRK), is a country in East Asia. It constitutes the northern half of the Korea, Korean Peninsula and shares borders with China and Russia to the north, at the Yalu River, Y ...

. It was an astronomical observatory during the Koryo period. Now only a granite platform remains, the sides of which coincide with the main

cardinal points The four cardinal directions, or cardinal points, are the four main compass directions: north, east, south, and west, commonly denoted by their initials N, E, S, and W respectively. Relative to north, the directions east, south, and west are at ...

. Dating from the early 10th century, it is regarded as the oldest structure for astronomical surveys in the world (together with its counterpart in

Kyongju Gyeongju ( ko, 경주, ), historically known as ''Seorabeol'' ( ko, 서라벌, ), is a coastal city in the far southeastern corner of North Gyeongsang Province in South Korea. It is the second largest city by area in the province after Andong, ...

). The

Goryeosa The ''Goryeosa'' (), or ''History of Goryeo'', is the main surviving historical record of Korea's Goryeo dynasty. It was composed nearly a century after the fall of Goryeo, during the reign of King Sejong, undergoing repeated revisions between ...

describes the structure: “Chomsongdae is west of the Manwoldae. It looks like a squared watchtower made of stone columns, seven chok (210cm) on each side and eight chok high (240cm). In the old days there was an apparatus for surveying the heavens, but now it is covered heavily with ivy and is antique-looking.” In 1936, the structure was described as follows: "The present status of the observatory consists of a stone platform about ten feet square supported by five upright stones ten feet high. On the top of the platform at the corners are holes in the stones about six inches in diameter that appear like footings for pillars to support another story." The structure is made of over 360 granite stones, indicative of the passage of one year. It was used for astronomical and meteorological observation, with equipment at the top used in the observation of changing weather and the movement of celestial bodies. It is listed as one of the

National Treasures of North Korea A National Treasure (국보; 國寶 : ) is a tangible artifact, site, or building deemed by the Government of North Korea to have significant historical or artistic value to the country. History The first list of Korean cultural treasures was des ...

. A one-third scale model of the Observatory is on display at the

Korean Central History Museum The Korean Central History Museum( ko, 조선중앙력사박물관) is a museum located in Pyongyang, North Korea.) The museum is located at the north end of Kim Il-sung Square. It contains displays on Korean history from primitive society to the m ...

. A larger model is also in front of the National Science Museum in South Korea, featured as an outdoor exhibit.

References

{{coord, 37.9747, N, 126.5306, E, source:wikidata, display=title National Treasures of North Korea Goryeo Astronomy in Korea Science and technology in Korea Kaesong Buildings and structures in North Hwanghae Province World Heritage Sites in North Korea Historic Monuments and Sites in Kaesong