Since the division of the Korean Peninsula in 1948, South and North Korea have independently developed their astronomical almanacs: Ryeokseo at the Korea Astronomy and Space Science Institute in South Korea and Cheonmunryeok at the Pyongyang Astronomical Observatory in North Korea. This study compares Ryeokseo and Cheonmunryeok for the year 2015, focusing on publication systems, content, terminology, and differences in data calculation methods. Additionally, it examines the calendars of South and North Korea from 2018 to 2023, analyzing similarities and differences in the representation of calendrical dates, public holidays, and other related aspects. The findings reveal that while the structure and content of the astronomical almanacs are similar in both countries, notable variances exist in the versions of ephemerides, time scales, and calculation precision. Consequently, identical data points are often recorded with slightly different values in each country's almanacs. Furthermore, approximately 28% of the terms used in North Korea's astronomical almanac are either not utilized in South Korea or have different definitions. Regarding calendar systems, those of South and North Korea are largely similar, resulting in no significant discrepancies in dates. However, there are notable differences in the observance of public holidays. While traditional holidays are common to both, most holidays are distinctively celebrated. Notably, North Korea does not observe religious holidays, and many of its holidays are associated with the regime.

이 논문은 민력의 이사 택일 이론을 천기대요와 협길통의의 내용과 비교⋅고찰한 것이다. 민력의 이사 택일 이론은 대부분 천기대요와 협 길통의에서 문헌적 근거를 찾을 수 있었다. 민력에 있는 이사 택일 이론의 원리는 年, 月, 日, 時를 기준으로 분류할 수 있다. 민력의 택일 이론은 한 가지 원리가 들어간 것은 드물고, 대부분 두 가지 이상의 원리가 결합된 것 이다. 택일 이론들의 역학적 원리를 보면, 八卦를 기반으로 선천팔괘와 후 천팔괘를 사용한 것이 있고, 河圖洛書를 기반으로 洛書九宮, 三元年·月·日 九星紫白, 生氣福德등을 사용한 것이 있다. 六十甲子와 干支를 기반으로 天 干⋅地支, 六十甲子, 甲旬法등을 사용한 것이 있고, 天文과 기타를 기반으 로 12月, 한 달, 30일, 춘하추동, 사계, 24절기, 북두칠성, 월삭, 공망 등을 사용한 것이 있다. 주제어: 민력, 택일, 이사 택일, 역학적 원리, 신살.

아시아 주요국으로 ‘Shine Muscat’ 포도를 수출하기 위하여 수출대상국의 농약잔류허용기준(MRL)에 적합하며 안정적이고 우수한 품질의 포도를 생산할 수 있는 포도 병해 방제력을 개발하고자 하였다. 경북 경산과 상주 지역의 간이비가림시설에서 재배되는 ‘Shine Muscat’ 포장에서 수출 대상국에서 허용 된 약제 중에서 포도 재배에 많이 사용되는 살균제를 선발하였고, 재배 기간 동안의 병해 발생을 방제하기 위하여 개화전부터 성숙기까지 10-11회 살포하였다. 2년에 걸쳐 약제를 살포하고 수확 전 병해 발생 여부를 조사하고 수확 후에는 과실의 품질 특성과 잔류 농약을 분석하였다. 갈색무늬병, 노균병, 탄저병이 발생하였으며, 2019년 2번 처리구에서 전체적으로 82% 이상의 방제가를 나타내었다. 과실 품질 특성은 지역별로 약간의 차이를 나타냈고 모든 처리구에서 농약 잔류량은 0.00-0.20 mg/kg 수준으로 주요 수출국의 MRL 이하로 검출되었다. 본 연구에서는 최근 수출량이 증가하는 ‘Shine Muscat’ 포도 재배에 활용할 수 있으며 안전한 수출용 포도를 생산할 수 있는 병해 방제력을 개발하였으며, 국내의 포도 수출 농가에 도움이 될 것으로 생각된다.

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.

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.

미포장충류(Nosema spp. (NS))는 양봉꿀벌에 심각한 문제를 야기시키는 기생충으로 효과적인 방제물질의 선발이 무엇보다 중요하다. 본 연구는 노제마병과 기타 꿀벌의 발생유행시기의 구명과 더불어 3가지 노제마병 방제물질(M1 = 벌꿀희석의 레몬쥬스; M2 = 설탕시럽 혼합의 카모마일 추출물; M3 = 설탕시럽 혼합의 항생물질 스트리베트)을 평가하고자 수행하였다. 꿀벌 성충과 유충집단의 질병 유행시기를 년간 조사하였으며, 야외 및 실험실 조건에서 노제마병에 대한 M1, M2, M3의 효과를 평가하였다. 조사결과 극소수의 꿀벌 성충과 유충 질병이 발견되었다. 노제마 병은 겨울과 봄 기간 저온과 고습조건에서 검출되었다. 포장실험에서 M2는 36.66%까지 발병억제 능력을 보였으며, 반면M3는 23.33%, M1는 13.33%의 억제효과를 보였다. 실내실험에서 M2가 방제효과가 가장 좋았고, 그 다음 M1와 M3 이었다. 3가지 방제물질은 병에 감염된 꿀벌성충의 생존력을 크게 높이는 것으로 나타났다. 본 연구는 노제마병 방제를 위한 천연물질로 카모마일의 잠재적 방제효과를 제시하고 있다.

We study the operation of a lunisolar calendar in Korea and its time data calculation method. The dates based on the lunisolar calendar have been conventionally used in Korea after the Gregorian calendar was introduced in 1896. With the Astronomy Act enacted in 2010, the lunisolar calendar is presently being used as an official calendar along with the Gregorian calendar. However, no institutionalized regulations have been provided on the time data calculation method by the lunisolar calendar. The Korea Astronomy and Space Science Institute very recently established the regulations on the lunisolar calendar operation in Korea. We introduce the regulations together with historical substances and analyze the time data calculated according to the regulations for 600 years from 1901 to 2500. From our study, we find that the value of ΔT (i.e., the difference between the terrestrial time and the universal time) is the most critical parameter causing uncertainty on the data. We also find that all new Moon days in the almanacs agree with our calculations since 1912. Meanwhile, we find that new Moon and winter solstice times are found to be very close to midnight in 38 and five cases, respectively. For instance, the new Moon time on January 14, 2097 is 0 h 0 min 8 s. In this case, deciding the first day (i.e., new moon day) in a lunar month is difficult because of the large uncertainty in the value of ΔT. Regarding with a lunar leap month, we find that the rules of inserting the leap month do not apply for 17 years. In conclusion, we believe that our findings are helpful in determining calendar days by using the lunisolar calendar.

We investigate the records related to the reign style and the calendar day from the epigraphs of the Goryeo dynasty (918 - 1392) in Korea in order to verify and supplement the sexagenary cycle data of the first day in the lunar month of the dynasty. The database of the National Research Institute of Culture Heritage contains a rubbed-copy image, transcription statement, and translation statement for Korean epigraphs as well as 775 epigraphs corresponding to the Goryeo dynasty. The epigraph records are valuable in that, during this time, they were written differently from other historical literature such as the Goryeosa (History of the Goryeo Dynasty), which was compiled in the next dynasty. We find that the Goryeo dynasty, in general, had adopted the reign styles of Chinese dynasties at that time. We also find 159 calendar day records all showing good agreement with the work of Ahn et al. except for dozens of records. Through this study, we can verify the reign styles and the calendar days of the Goryeo dynasty.

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.

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.

Il-Cohin of the 24 subseasons is found to be repeated in the period ut 103, solar yeors. And that of the date in the old Chinese calendar xear is, repeating in the period of 102 solar years. It is also found that the length of lunar month is repeating in nearly 64solar years.

The interpolation formula Chao-ch'a-shn devised for the Chinese calendar, Shou-shih-li, has been shown as the one of the 3rd order polynomial. Its 3 coefficients have been determined from the table of the Sun in Shou-shih-li. Its applications to the moon and planets are also briefly mentioned.

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.

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.