A study on making a Honsang using the star catalogue from 『Seong Gyeong』

Abstract The first record of Honsang (Celestial globe) was found in 『 Sejong Sillok 』 in Korea. Since then, there were records that Honsang was restored during the reign of King Jungjong and King Myungjong , and then restored again in the reign of King Seonjo . The only existing Honsang was made by Yi Hwang (1501–1570) in the 16th century for education of his followers. After then, Hong Dae Yong ’ s (1731–1783) Honsangui , which was made in 18th century, had been passed down only through the literature. The constellations in Honsang and the scale system of each ring changed after 17th century when Western science began to affect Joseon dynasty. Since that time, the constellations, realized on Honsang globe, changed from constellations in the old method to ones in the new method. Furthermore, the scale system of rings on Honsang was changed from 365.25 Do , Jucheondo (Celestial globe circumference), to 360°. In this study, Honsang with constellations in the new method was made using star catalogue from 『 Seong Gyeong 』 published in 1861, which represented the constellations in the new method of Joseon dynasty. In order to realized the constellations from the star catalogue in 『 Seong Gyeong 』 on Honsang globe, the plane star chart and circular star chart of the area near the South and North Poles were drawn using spherical trigonometry. Using these star charts, the constellations in whole sky including stars near the South Pole were realized on Honsang globe. Also, equatorial coordinates and ecliptic coordinates were realized on Honsang globe simultaneously, and scales of Honsang ’s rings were marked as 360°.