We investigate the astronomical phenomenon records of Sukjong’s 𝐶ℎ𝑢𝑛𝑏𝑎𝑛𝑔-𝐼𝑙𝑔𝑖 made by 𝑆𝑖𝑔𝑎𝑛𝑔𝑤𝑜𝑛 (Royal Educational Office of the Crown Prince) at which King Sukjong was the crown prince (i.e., 1667 January 24–1674 September 22). From the daily records of 2,799 days, we extract the astronomical records of 1,443 days and classify them into 14 categories. Then, we group the records of each category into five phenomena (Atmosphere, Eclipse, Daylight Appearance, Apparition, and Appulse) and compare them with the results of modern astronomical computations wherever possible. Except for Atmosphere group comprising records of meteorological events, such as solar halo, lunar halo, and unusual clouds, the significant findings in every other group are as follows: In Eclipse group, the solar eclipse that occurred on 1673 August 12 was unobservable in Korea, which is in contrast to the record of 𝐽𝑜𝑠𝑒𝑜𝑛𝑤𝑎𝑛𝑔 𝑗𝑜-𝑆𝑖𝑙𝑙𝑜𝑘 (Annals of the Joseon Dynasty), which states that the sun was in eclipse around sunset time, as observed at 𝑁𝑎𝑚 mountain. From the lunar eclipse records, we verify that the Joseon court did not change the date of the events observed after midnight. In Daylight Appearance group, we confirm that this phenomenon was observed during the daytime and not during twilight. We further suggest that if observation conditions are met, a celestial body brighter than −2.3 mag could be seen during the daytime with the naked-eye. In Apparition group, we find the possibilities that the Orionid meteor shower had influence on the meteor records and the seasonality on the aurora records. We also find that the Korean records in which the coma of comet C/1668 E1 was located below the horizon were overlooked in previous studies. Finally, we find that the records of Appulse group generally agree with the results of modern calculations. The records of 𝐵𝑒𝑜𝑚 (trespass in literal) and 𝑆𝑖𝑘 (eating in literal) events show average angular separations of 1.2◦ and 1.0◦, respectively. In conclusion, we believe this work helps study the astronomical records of other logs of 𝑆𝑖𝑔𝑎𝑛𝑔𝑤𝑜𝑛, such as Sunjong’s 𝐶ℎ𝑢𝑛𝑏𝑎𝑛𝑔-𝐼𝑙𝑔𝑖.

Abstract
1. Introduction
2. Sukjong’s Chunbang-Ilgi
    2.1. Outline
    2.2. Modern Computations
    2.3. Distribution of Records
    2.4. Classification of Records
3. Analysis
    3.1. Atmosphere Group
    3.2. Eclipse Group
    3.3. Daylight Appearance Group
    3.4. Apparition Group
    3.5. Appulse Group
4. Summary and Conclusion
Acknowledgments
Appendix A. Donggung-Ilgi
Appendix B. Terminology
References

• Ki-Won Lee(Francisco College, Daegu Catholic University) Corresponding Author