LAUSR

Abstract We analyzed astronomical data in the Tongmunhwigo, one of the history books containing diplomatic documents of the Joseon government (the last dynasty of Korea). This book contains predictions of solar and lunar eclipses for Seoul and Beijing with specific information such as magnitude and time, sent by the Qing government to the King of Joseon between 1721 to 1881. We analyzed the accuracy of the calculations performed by Qing’s astronomers, by comparing them with the results of modern calculations. Overall, the error value for time of the eclipses was less than ± 0.5 h ( ± 30 min) and the error value for magnitude was within ± 10 % . The results of this study will be helpful for understanding how accurate the predictions calculated by Qing astronomers were during the eighteenth to nineteenth centuries.