In 1645, soon after the Qing dynasty adopted the Jesuit-devised Shixian li as its official calendrical system, the Joseon court launched a project to learn the methods of the new Jesuit calendar. For over a century thereafter, the Joseon court sent a series of official missions to Beijing to learn calculation methods from the Jesuit and Qing astronomers. Contrary to previous historical accounts that portrayed this process as the introduction of “Western science” into Korea, this paper relocates the late Joseon episode of learning Western astronomy into a more proper historical context, of the politico-scientific relations of the Qing and Joseon dynasties, and suggests that the late Joseon project to learn Western astronomy might be better viewed as an attempt to introduce the astronomical system of a new ruling dynasty of the China continent. The Qing-Joseon politico-cultural relations, this paper argues, provided the Joseon court with the basic motive for its attempt to adopt Western astronomy; the actual process of the astronomy project, including its timing and the ways of carrying out businesses, was also conditioned by ever changing features of the Qing-Joseon relationship; Finally, that relationship was not a mere “external” factor that only accelerated or inhibited the government astronomy project; it also played a role that might be called epistemological, in the sense that it fundamentally shaped how astronomers and literati officials at Joseon court viewed the “outer worlds”—the world of stars, as well as that of another culture called “the West.”