초록 열기/닫기 버튼
『칠정산내편』이 편찬된 후에 이어진 역산 수식의 정비와 개정을 담은 책이 세조 4년에 간행된 『交食推步法假令』이다. 이 글에서는 영축차, 지질차, 가감차, 일출입분, 정한행도, 적도황도수도 등 여섯 항목의 算術이 『칠정산내편』 이후에 어떻게 개선되었는지를 밝히는데 주력하였다. 입성을 쓰지 않고도 곧바로 값을 얻기 위해 도입한 새 방식은 무엇이며 산법이 간편하고 정밀해졌다는 의미는 무엇인지를 드러내기 위해 『수시력경』의 元史法과 『칠정산내편』의 立成法에 비해 어느 부분이 新術로 바뀌었는지를 예제와 더불어 자세하게 밝혔다. 또 유일하게 『교식추보법가령』에만 담겨있는 개정된 가감차 산식에 대해서도 살펴보았다. 달의 운행속도만으로 나타내던 가감차의 속도항을 『교식추보법가령』에서 처음으로 일월간 상대속도로 바꾸게 된 연유가 어디에 있는지를 전후의 정황을 분석하면서 추적해보았다. 이런 가운데서 『칠정산내편』 제정 이후 『교식추보법가령』이 나오기까지 교식추보법 자체를 바라보는 조선의 시각에 어떤 변화가 일어났는지, 인식의 변화를 일으킨 요인은 무엇이었는지를 살피는데도 관심을 기울였다.
Soon after the compilation of Chiljeongsan-naepyon (七政算內篇) in 1444, some parts of Joseon's first domestic calendar system were revised and improved during the reign of King Sejong. Several arithmetic formulae were modified to make the prediction of the eclipse simple and convenient. The frequent and onerous recourses to the bulky ready reckoning tables were phased out of the calculation procedure owing to the new formulae invented by Joseon mathematical astronomers. All the contents of improvement were reflected in the Book of Explanations and Exercises for Eclipse Prediction, Gyosikchubobeob Garyong (交食推步法假令), which was published in 1458, the fourth year of King Sejo’s reign. The first part of this article reports on the details and effectiveness of the newly devised arithmetic to calculate the following six items: the expansion/contraction difference of the sun, the slackening/hastening difference of the moon, the addition/subtraction difference for eclipse correction, the sunrise/sunset parts of a day, the corrected extent motion degrees at the eclipse maximum, and the lodge positions on the Red/Yellow Way. The rest of the article deals with the meaning and the origin of the newly defined formula for addition/subtraction difference used to obtain the corrected time of the conjunction and the full moon. It attracts remarkable attention because the angular speed of the moon relative to the sun was considered for the first time in the long history of East Asian calendars, in the denominator of the formula for the addition/subtraction difference for eclipse correction. Moreover, some concern was paid to explain how and why King Sejong’s point of view on the results of eclipse prediction had changed generously during the progress of establishing his own calendar from Chinese systems.
키워드열기/닫기 버튼
『Gyosikchubobeob Garyong』, 『Chiljeongsan-naepyon』, Shoushi-li, Expansion/contraction difference, Slackening/hastening difference, Addition/subtraction difference, Sunrise/sunset parts, Corrected extent motion degrees, Lodge positions on the Red/ Yellow Way
