• 천문학논총
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• 제34권3호
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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 Astronomy and Space Sciences
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• 제36권2호
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• pp.87-96
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• 2019

We investigate solar and lunar motions in the Seonmyeong (SM) calendar that was compiled by Xu, Ang of the Tang dynasty (A.D. 618-907) in China and used for 71 years from 822 to 892. This calendar was also used in Korea during the Goryeo dynasty (A.D. 918-1392) and in Japan for 823 years from 862 to 1684, the longest time among the three countries. Referring to historical documents of China, Korea, and Japan, we analyze the calendrical methods of calculating the daily apparent movements of the Sun and Moon in the SM calendar, which were considered their unequal motions, and compare the movements with the results of modern calculations for three periods in the Goryeo dynasty: 919, 1155, and 1392 years (i.e., the beginning, middle, and ending of the dynasty, respectively). We find that a quadratic equation was employed to obtain the daily movement of the Sun using physical quantities on the instant of each solar term, which was tabulated in its calendar book such as the Goryeosa (History of the Goryeo Dynasty). For quantitative analysis, we compute the mean absolute difference (MAD) of the daily apparent movement between the SM calendar and modern calculations and obtain 0.33, 0.30, and 0.31 arcmin for the periods of 919, 1155, and 1392 years, respectively. Meanwhile, we find relatively large MAD values in the daily movement of the Moon: 0.217, 0.284, and 0.240 degrees for each corresponding year. An interesting point is that the MAD value in the lunar motion shows the maximum in 1155 years, and is the minimum in the solar motion. In conclusion, we believe that this study will facilitate in the understanding of the SM calendar further, particularly in the calendrical methods of calculating sunrise, sunset, and eclipse times.

• 천문학회지
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• 제1권1호
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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.

• 천문학논총
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• 제35권1호
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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.

• 천문학회보
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• 제39권2호
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• pp.72.1-72.1
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• 2014

In the Joseon Dynasty, A day divided into 100 gak (刻, approximately a quarter) or 12 Sijin (時辰, double hours) that was composed of half-Sijin as Cho (初, beginnings of double hours) and Jeong (正, mid-points double hours). The timekeeping system was changed from 100 gak to 96 gak with using $sh{\acute{i}}xi{\grave{a}}n$ calendar (時憲曆) in 1654. And then 12 Sijin was changed to the 24-hours system in the same manner as current with the enforcement of the solar calendar (太陽曆) in 1896. We examine the record of the timekeeping system and notation of hours from the astronomical almanacs and official gazettes during 50 years after 1896. The Korean Empire Government first adopted the standard meridian of the Gyeongseong (former name of the Seoul in Korea) in 1908. However the mean solar time was applied to the almanac since 1913. After 1896, the year of enforcement of the solar calendar, the expression of times on a Korean almanac was written with O-jeon (午前, morning) and O-hu (午後, afternoon). The definition of 1day 24-hours system was first stated by the legislation in 1900. The expression of times was used 24 hours without O-jeon and O-hu in 1916. In daily life, the 24-hours system has used in parallel with 12-hours system divided into morning and afternoon even today.

• 천문학논총
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• 제30권1호
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• pp.1-9
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• 2015

The National Foundation Day of Korea (개천절, 開天節) is currently celebrated on October 3 in Gregorian calendar. We review the history of dating the National Foundation Day of Korea and make a suggestion that it be celebrated on October 3 in the lunar calendar. We present numerous historical records on heaven-worship rites supporting the date October 3 in the lunar calendar. It is pointed out that October 3 in the solar calendar has been adopted in 1949 by the National Assembly with the thought that the lunar calendar is inferior and behind the times. The thought originates from misunderstanding on the value of the lunar calendar and from the ignorance of importance of history and tradition. Since there are now many national holidays that follow the lunar calendar, the logic of the National Assembly in 1949 also makes no sense. We emphasize that the lunar calendar should be followed for the National Foundation Day of Korea for its historical and symbolic characteristics restoration. We also investigate the year of the foundation of the first country of Korea, Dangun Joseon. It is found that even though the majority of the literature before late 15th century recorded the beginning year of Dangun Joseon dynasty to be equal to that of Liao Dynasty (堯), it was accidentally changed to the 25th year of Liao Dynasty in 1484 through a misinterpretation of the previous records. We claim that the beginning year of Dangun Joseon should be set to that of Liao Dynasty as recorded in the original literature in the earlier days. According to the two main opinions accepted by Korea, the beginning year of Liao Dynasty was 2357 B.C. or 2333 B.C., which correspond to the year of Gap-Jin (the 41st year of the sexagenary cycle) or Mu-Jin (the 4th year of the sexagenary cycle), respectively.

• 천문학회지
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• 제33권3호
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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

• 대한한의학원전학회지
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• 제20권1호
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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.

• Journal of Astronomy and Space Sciences
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• 제21권4호
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• pp.493-504
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• 2004

동아시아의 역사서에는 일식에 대한 기록들이 다른 천문현상들에 비해 많이 나타난다. 이것은 전통적으로 일식은 왕조의 운명과 연관되어있다는 정치적인 사상 때문이다. 조선시대까지도 태양은 임금을 상징하였고, 일식이 일어나면 일식이 무사히 지나가도록 임금이 제사하는 구식례(求食禮)을 지내곤 했다. 따라서 당시의 임금은 일식에 대한 정확한 예보를 얻는 것이 상당히 중요한 일이었다. 그러나 그럼에도 불구하고 조선 초기의 일식 예측은 잘 맞지가 않았다. 이에 세종은 당시 수도인 한양의 위치에 맞는 역법서(曆法書)인 칠정산내편과 칠정산외편을 편찬하였고, 이로 인해 비로소 조선의 자주적인 역법(曆法)이 확립되었다. 칠정산외편은 아라비아의 역법인 회회력(回回曆)을 기초로 해서 만들어진 역법으로 조선 초기의 일식 계산에서는 당시의 여러 역법 계산 결과보다 더 정확하였고, 현대적인 계산 방법과 비교하여 보아도 오차의 범위내에 잘 들어맞음을 알 수 있었다.

• 천문학회보
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• 제36권2호
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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.