Redefining the Sky of Joseon – The Scientific Brilliance of Chiljeongsan Naeoe-pyeon
Redefining the Sky of Joseon – The Scientific Brilliance of Chiljeongsan Naeoe-pyeon (from Volume 156 of the Veritable Records of King Sejong) During the Goryeo Dynasty, Choi Seongji accompanied King Chungseon on a visit to the Yuan Dynasty in China. There, he obtained a copy of the Shoushili Calendar (授時曆法) and brought it back to Korea, where it was adopted for the first time. However, at the time, local calendar officials only understood how to construct the calendar itself. They lacked the knowledge to calculate solar and lunar eclipses or determine the positions of the five planets—Mercury, Venus, Mars, Jupiter, and Saturn. In response, King Sejong commissioned Jeong Heumji, Jeong Cho, and Jeong Inji to conduct astronomical research and refine the calendar system. These scholars successfully unraveled the underlying principles. Where their understanding fell short, King Sejong himself, with his keen insight, discerned the correct interpretations. Moreover, the Joseon cou...