We have uncovered 14 Korean royal astronomers and one scientist who worked in the early and mid-18th century. In spite of their high positions in the government office, all of them but one were not recorded anywhere in the major histories, such as WangjoSillok (王朝實錄) and JeungboMunheonBigo (增補文獻備考). Our search of Bon'gwans for each person has been carried successfully for 13 scientists. Their family relations are also uncovered finding five eminent astronomy families.

This paper will introduce and overview in general the Seongbyeon Deungrok issued by the Gwansang-gam, the Astronomical Board in the Joseon Dynasty of Korea. All the Chinese characters in the 1668 Seongbyeon Deungrok was deciphered at first and these were translated into Korean and English. With these translations and the word ‘white vapor’ in particular we discuss the nature of the main object in this Deungrok. Lastly, names of observers who engaged in the observations of this 1668 celestial, which are made as a by-product of this research, are introduced.