Cheonsang yeolcha bunyajido carved

Under King Taejo, a star chart based on a rubbing of a Goguryeo astronomical map was corrected and carved in stone as the Cheonsang yeolcha bunyajido.

The Goguryeo star chart carved in stone at Pyongyang had sunk into the Daedong River during a war, and only a rubbing survived. To show that the new dynasty held the mandate of heaven, Taejo had a new chart made from this rubbing. The Bureau of Astronomy corrected the positions of the constellations that had shifted since, and in 1395 the chart was carved on black stone, with calculations by Ryu Bang-taek and a text by Gwon Geun.

The name means a chart dividing the sky near the equator into twelve sectors, each matched to a region on earth. It shows 1,467 stars. Carrying on Goguryeo astronomy, it marked the start of Joseon astronomy, which continued with Sejong’s armillary spheres and the Chiljeongsan. The original stone is now in the National Palace Museum of Korea.