• Journal of The Korean Astronomical Society
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• v.45 no.4
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• pp.85-91
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• 2012

Astronomical data making such as forming a calendar, period of day, determining the time of rising/setting of the sun and the onset of twilight are essential in our daily lives. Knowing the calendar day of the past is particularly crucial for studying the history of a clan or a nation. To verify previous studies in the calendar day of the Joseon dynasty (1392 - 1910), we investigate the sexagenary cycle of the new moon day (i.e., the first day in a lunar month) by using sources such as results of the calculations using the Datong calendar (a Chinese Calendar of the Ming Dynasty) and the data of Baekjungryeok (a Perpetual Calendar; literally, a one hundred-year almanac). Compared with the study of Ahn et al., we find that as many as 17 sexagenary cycles show discrepancies. In the cases of nine discrepancies, we find that the sexagenary cycles of this study are identical to those of the almanacs at that time. In addition, we study five sexagenary cycles by using the historical accounts of Joseon Wangjo Sillok (Annals of the Joseon Dynasty), Seungjeongwon Ilgi (Daily Reports of Royal Secretariat), Chungung Ilgi (Logs of Crown Prince), and so forth. For the remaining discrepancies, we present historical literature supporting the results of this study. This study will greatly contribute to the identification of the lunisolar calendar days during the Joseon dynasty as the dates of the modern (i.e., Gregorian) calendar.

• Journal of Korean Medical classics
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• v.20 no.1
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• pp.113-123
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• 2007

The astronomical understanding of the heavens in "Hwangje-Naegyeong" can be divided into three main fields: the theory of cosmos, astronomy and calender. "Hwangie-Naegyeong" comprised the theory of cosmos, astronomy and calender established in the Han period. Astronomy was to describe the heavenly world and to interpret its phenomena. Calendar was to make numerical representations of the observations of all kinds of celestial bodies and to give them number-mystical meanings. Theory of cosmos treated what ancient Chinese speculated on the structure of the heavens including the earth. These three fields developed independently. However, they can also be be combined into one tradition, the astronomical knowledge. In the Han period that the astronomical knowledge grew from the mere accumulation of primitive knowledge to the established form. Throughout the Chinese history, the essential contents of astronomical knowledge including the theory of calendar, did not change much from what they were in Han period. "Hwangje-Naegyeong" use the lunisolar calendar(太陰太陽曆) and the Calendar in the late Han period(後漢四分曆). The use of the subdivisions of the seasons(24節氣) and the leap month(閏月) in "Hwangje-Naegyeong" means that it adopted the lunisolar calendar. Also "Hwangje-Naegyeong" adopted the Calendar in the late Han period by the four points: "Hwangje-Naegveong" ruled the circulation of the universe(周天度數) at 365, 1/4 terms, use the The Twenty Eight Constellations in astronomical observation, view the heavenly body by the ecliptic(黃道) and mark down year by the Heavenly Streams & Earthly Branches(干支紀年), The 24 solar terms is made by amount of Yang-Gi(陽氣) and samyum and samyang(三陰三陽) represent the amount of Yang-Gi in the earth.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.2
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• pp.138.2-138.2
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• 2011

Astronomical data such as calendar day and time of rising/setting of the sun and onset of twilight are essential in our daily lives. Knowing the calendar day of the past is particularly crucial for studying the history of a clan or a nation. To verify previous studies on the calendar day of the Joseon dynasty (1392 - 1910), we also investigated the sexagenary cycle of the new moon day (i.e., the first day in a lunar month) using different sources: results of the calculation by the Datong calendar (a Chinese Calendar of the Ming Dynasty) and data of Baekjungryeok (a Perpetual Calendar - literally, a one hundred-year almanac). Compared with the study of Ahn et al., we have found that as many as 17 sexagenary cycles show discrepancies. In the case of nine discrepancies, we found that the sexagenary cycles of this study are identical to those of the almanacs at that time. In addition, we study six sexagenary cycles by using the historical accounts of Joseon Wangjo Sillok (Annals of the Joseon Dynasty), Seungjeongwon Ilgi (Daily Records of Royal Secretariat), Chungung Ilgi (Logs of Crown Prince), and so forth. We present historical materials supporting the results of this study for the remainder. In conclusion, we think that this study will greatly contribute to the comparison between luni-solar calendar days during the Joseon dynasty and those in the modern (i.e., Gregorian) calendar.

• Journal of The Korean Astronomical Society
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• v.11 no.1
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• pp.47-54
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• 1978

Twelve Chih was sasigned to each day in the old Chinese calendar. This paper clarifres the relations between 12 Chih and the diurnal motion of Big Dipper or the clock, and it shows the long term table and formula for the dayly assignment of 12 Chih in the calendar.

• Journal of The Korean Astronomical Society
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• v.1 no.1
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• pp.19-27
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• 1968

A simple method for solar-lunar calendar conversion is obtained by means of Meton period for the convinience of the date conversion in the study of the old records of astronomical observations in Korea.

• Publications of The Korean Astronomical Society
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• v.34 no.3
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• pp.49-65
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• 2019

We investigate the provenance and the changes in the timekeeping system focusing on official records such as almanacs and textbooks published by the government after the solar calendar was introduced. We found that the solar calendar and the 12-hour clock time first appeared in 1884 during Joseon dynasty, at that time the solar calendar was used at the open port in Busan to facilitate the exchanges with Japan. The 12-hour clock time first appeared in the 『Hansung Sunbo』 published by the government in 1884. We also found that the Joseon dynasty also used 12 diǎnzhōng or 12 diǎn. In addition, the term of the 'Sigan' first appeared in the first official academic textbook in August 1895, and the chapter related to time contained the information about 12-hour clock time instead of the 12 Shi. In 1908, the meaning of the solar time, the equation of time, and the differences in longitude with the adoption of Korean Standard Time were introduced. Meanwhile, the 24-hour clock time was first introduced in Joseon and applied to railway times in 1907. The 1946 almanac, the first issue after liberation, used the 12-hour clock time which uses 'Sango', 'Hao' and the 24-hour clock time started to be used from the following year and is still used to this day. Finally, the 12-hour clock time, which was introduced around 1884, was enacted as Article 44 of the law in 1900 and was revised again in 1905 and 1908. In Korea, the terms related to the time in the current astronomical calendar system were newly defined around 1884, 1896, and 1908, and gradually standardized through the establishment of laws.

• Journal of The Korean Astronomical Society
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• v.33 no.3
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• pp.177-183
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• 2000

We arrange Korean ancient calendar with Solar calendar during Choseon Dynasty(A.D. 1392-1910). In this period, we have one representable history books and several books, and most of information for date are found from them, ChoseonWangjosillok(조선왕조실록) and Jeungbomunheonbigo(증보문헌비고), etc. In those books many astronomical data and calendar information data are contained, so we can make chronological tables. Most of the data are arranged based on those several books, and for doubtable data are identified from eclipse, historical events and lunar phase calculations etc. We find that arranged chronological tables during Choseon Dynasty are similar to that of China and somewhat different from that of Japan. In addition we summarize all misrecorded date data in ChoseonWangjosillok

• Publications of The Korean Astronomical Society
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• v.30 no.3
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• pp.789-800
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• 2015

During the Joseon dynasty, the Gwansanggam (觀象監, The Royal Astronomical Observatory) was the royal administration in charge of Astronomy (天文), Geography (地理), Calendars (曆), Astronomical and meteorological observation (測候), and Timekeeping (刻漏). Of those affairs, the Astronomical Almanac compilation was most important. In this paper, we study the education and selection of astronomical officials in the 19th century during the Joseon dynasty, focusing on Astronomical Almanac officials. According to this study, their main area was calendar calculation, and they were involved in Astronomical Almanac compilation for nearly 40 years, until they resigned. In addition, they served as Samryeok-susulgwan (三曆修述官, Official for calendar calculation by the $Sh{\acute{i}}xi{\grave{a}}n$ calendar), and Ilgwa-gamingwan (日課監印官, Official printing supervisor). To undertake these core duties, an official had to pass several examinations and courses. The Gwansanggam (after Gwansangso) carried out the educational function for the officials. In particular, reserved officials of the astronomy division had to be educated starting with a trainee course.

• Publications of The Korean Astronomical Society
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• v.32 no.2
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• pp.367-380
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• 2017

The life and astronomical activity of Lee Deok-Seong (李德星, 1720-1794) was studied using various historical sources, including the astronomical almanac, Seungjeongwon-Ilgi (Daily records of Royal Secretariat of Joseon dynasty), and the Gwansang-Gam's logbooks during Joseon dynasty (A.D. 1392-1910). We present the results of the study including the following main findings. First, from the investigation of Lee's family tree, we find that a number of his relatives were also astronomers, notably Samryeok-Gwan (三曆官, the post of calendrical calculation). Second, we find that he took part in the compilation of an annual astronomical almanac over a period of at least 16 years. His major achievements in the astronomy of the Joseon dynasty were to establish a new method of calendar-making calculation and to bring astronomical materials to the Joseon court through a visit to China. The Joseon dynasty enforced the Shixianli (時憲曆, a Chinese calendar made by Adam Shall) in 1654 without fully understanding the calendar. So an astronomer and an envoy were dispatched to China in order to master the intricacies of the calendar and to learn as much of Western science as was available in that time and place. Lee Deok-Seong worked at the Gwansang-Gam (觀象監, Royal Astronomical Bureau) during the reigns of King Yeongjo (英祖) and Jeongjo (正祖). As best as we can ascertain in relation with the calculations in the Shixian calendar, Lee visited China four times. During his trips and interactions, he learned a new method for calendar-making calculations, and introduced many Western-Chinese astronomical books to Joseon academia. Lee greatly improved the accuracy of calendrical calculations, even while simplifying the calculation process. With these achievements, he finally was promoted to the title of Sungrok-Daebu (崇祿大夫), the third highest grade of royal official. In conclusion, history demonstrates that Lee Deok-Seong was one of the most outstanding astronomers in the late-Joseon dynasty.

• Publications of The Korean Astronomical Society
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• v.35 no.1
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• pp.1-16
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• 2020

We report a calendar sheet for the 31st year of the reign of King Gojong (1894) (hereafter, calendar sheet 1894) in Korea, which calendrical data in a single page. This calendar sheet 1894 is composed of 14 rows by 14 columns (about 190 cells), and various calendrical data are recorded such as the sexagenary circle of the first day in each month, 24 solar terms, full moon day. In this paper, we compare calendrical data of 1894 calendar sheet with those of the almanac based on the Shixian calendar (hereafter, annual almanac) of the same year. Our findings are as follows. First, we find that the year is expressed using the reign-year of the king of the Joseon dynasty differently from using the reign-style of China in the annual almanac those times. Other calendar days of this calendar sheet are the same as those of the annual almanac in term of lunar dates, 24 solar terms, sexagenary days and so forth. Second, we find that the calendar sheet 1894 contains memorial days for 64 lineally ancestors of the Joseon royal family. These royal memorial days appears in the annual almanac two years later (i.e., 1896). Third, as the most distinctive feature, we find that the symbol of 工 kept every two cells. It was found that the cells can be filled with three days as the maximum number of days and then are labelled the same symbol 工 every second cell. This feature allows us to get the first year in which this kind of calendar sheet was published. It is conjectured one of 11 years, such as 1845, 1846, 1847, 1873, 1874, 1875, 1876, 1877, 1878, 1879 or 1880. We also think that the format of the calendar sheet 1894 has influenced on the Daehan-Minryeok (Korean civil calendar sheet) of 1920.