Gwansanggam Jejo (觀象監提調) and Yeongsa (領事) were in charge of the operation of Gwansanggam (The office for Observation of Natural Phenomenon). During the reign of King Yeongjo, a tenure of Gwansanggam Jejo was shorter than that of King Sukjong’s mandate, and their appointment applied with Ssanggeohodaae (雙擧互對), method in which different party members were appointed to the positions of the two Jejo. However, during the reign of King Yeongjo, many Jejo were from the former Yeongsa and Jejo families. And the proportion of Jejo from the such family was higher than that of King Sukjong's reign. This situation is due to the implementation of Tangpyongchaek (蕩平策) allowed families, not mainstream forces, to participate in politics. During the reign of King Yeongjo, Gwansanggam Jejo was faithful to his role in maintaining and inheriting the existing regulations. At the same time, each of them played their role by revising various regulations in line with Almanac changes and changing the Gwansanggam organization and operating system accordingly. As a result, during the reign of King Yeongjo, Gwansanggam was able to implement a stable organizational system centered on astronomy.