Portable Plane Sundial

This was the most precise among the sundials made during the Joseon Period but was the smallest; it was carried on the body and used for measuring time. It showed that it had Seoul’s latitude as the standard. The name of the manufacturer (Kang Yoon) and the year of manufacture (1870) are engraved on it, making it academically valuable as a sundial.

The time can be determined by the shadow line indicated by the triangle along the hour and bar (time line) below. From the right, the interval is drawn differently depending on the inclination of the sun shadow from dawn (5:00-7:00 AM) to sunset (5:00-7:00 PM). You can read the time in 15-minute increments by placing dots at each angle (15-minute intervals). The compass is the opposite of the current magnetic north compass. Here, the characters engraved on the south signify true north with a azimuth of 0˚, and 15˚ in clockwise order represents a total of 24 directions.

This sundial is a scientific relic that shows the excellence of sundial manufacturing technology in the late Joseon Dynasty.