• 천문학논총
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• 제26권3호
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• pp.129-140
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• 2011

In this paper, we have studied Sogyupyo (小圭表, small noon gnomon) of the Joseon dynasty. According to the Veritable Records of King Sejong (世宗, 1418 - 1450), Daegyupyo (大圭表, large noon gnomon) with a height of 40-feet [尺] was constructed by Jeong, Cho (鄭招) and his colleagues in 1435, and installed around Ganuidae (簡儀臺, platform of Ganui). On the contrary, the details of Sogyupyo are unknown although the shadow length measurements by Daegyupyo and Sogyupyo are found on the Veritable Records of King Myeongjong (明宗, 1545 - 1567). By analysing historical documents and performing experiments, we have investigated the construction details of Sogyupyo including its development year, manufacturer, and installation spot. We have found that Sogyupyo would be manufactured by King Sejong in 1440 and placed around Ganuidae. And Sogyupyo would be five times smaller than Daegyupyo, i.e., 8-feet. On the basis of experiments, we suggest that although it is smaller, Sogyupyo was equipped with a bar [橫梁] and a pin-hole projector [影符] like Daegyupyo in order to produce the observation precision presented in the Veritable Record of King Myeongjong.

• 천문학회보
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• 제37권2호
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• pp.102.1-102.1
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• 2012

In this paper, we analyzed Korean historical records of the periodic comet Halley in three periods (Three Kingdoms, the Goryeo dynasty, and the Joseon dynasty) using various sources such as Samguksagi (History of the Three Kingdoms), Goryeosa (History of the Goryeo Dynasty), and Joseonwangjosillok (Annals of the Joseon Dynasty). To determine the apparition time of the comet at each return, we referred to the works of Kronk. For the Three Kingdoms period, we could not find any record relevant to Halley's comet from Samguksagi. Instead, we examined the suggestion that the phenomenon two Suns appearing on April 1, 760 (in a luni-solar calendar), which is recorded in Samgukyusa (Renaissance of the Three Kingdoms), indicates an appearance of comet Halley during the daytime. In contrast, we found that all the returns of Halley's comet during the Goryeo dynasty are recorded, although some accounts are questioned. In addition, we found that the appearance of Halley's comet in 1145 is also mentioned in a spirit-path stele made in 1178. For the Joseon dynasty period, we found that all the returns of the comet are recorded, as with the Goryeo dynasty, except for the return of 1910, in which the former dynasty fell. In conclusion, we think that this study will be helpful for understanding Korean historical accounts of Halley's comet.

• 천문학회지
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• 제53권6호
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• pp.125-138
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• 2020

We determine the observing sites for eclipses of large magnitude recorded in ancient Chinese chronicles from 200 BCE to 900 CE, by adopting the difference between terrestrial time and universal time, ΔT, given by Morrison & Stephenson (2004). The records of solar eclipses with large magnitude are divided into four groups in accordance with the historical variations of the capital cities of ancient Chinese dynasties. We determine areas in which all the eclipses in each group, with an eclipse magnitude larger than a certain threshold value, could be observed. We find that these areas coincide with the historical capitals, which agrees with the general idea that the solar eclipses were observed at the capital of each dynasty. This result also verifies the ΔT values during the period from 100 BCE to 400 CE, during which historical records of eclipses are so rare that the ΔT values can only be obtained by interpolating the long-term data. Moreover, we show that the eclipses described by the term Ji in East-Asian history are not all total eclipses; their mean magnitude is 0.96 ± 0.04. We find that complementary expressions, such as dark daytime and appearance of stars during the eclipse, strengthen the possibility that eclipses described by the term Ji were total. We also provide quantitative definitions for expressions such as 'being not complete and like a hook', 'being almost complete', 'visibility of stars during the eclipse', and 'darkness during an eclipse.' The literal meanings of these expressions are in agreement with the recent physical modeling of sky brightness during total eclipses provided by Können & Hinz (2008).

• Journal of Astronomy and Space Sciences
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• 제19권3호
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• pp.231-242
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• 2002

소간의는 천체의 위치를 관측하고 시간을 측정할 수 있는 천문 관측 기기로서 세종16년 (1434년)에 이천, 정초, 정인지가 제작한 천문의기 이다. 우리는 소간의의 문헌과 관측기록을 수집하여 정리하였다. 소간의는 적도좌표계와 지평좌표계를 선택하여 관측할 수 있어서 천체의 적경과 적위, 고도와 방위를 측정할 수 있다 그 구조는 사유환, 적도환, 백각환, 규형, 용주, 부(받침대)로 구성되어 있다. 소간의는 천체의 위치를 파악하는 것은 물론 주야의 시간 측정과 이동식 측량기로 활용할 수 있는 이동식 다목적 천문의기 이다.

• 천문학회보
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• 제27권1호
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• pp.36-36
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• 2002

별똥에는 가랑 별똥(sporadic meteors)과 별똥비 (meteor shower)에 속하는 별똥이 있다. 우리는 고려사 천문지에 적혀 있는 별똥 기록을 조사하여 10세기에서 15세기까지 지구 공전 궤도 상의 별똥 알갱이의 분포에 대해서 연구하였다. 우리는 일년중 특정한 날짜에 별똥이 많이 떨어지는 시기가 몇 개 있음을 발견하였다. 우리는 이러한 별똥들이 별똥비에 해당할 것으로 가정하고 한국, 일본, 중국의 천문 기록 가운데 별똥 소나기 기록을 끄집어 내어 고려사의 별똥 기록에서 구한 별똥비 기록과 비교하였다. 그 결과 7월 27일 경에 강한 별똥비가 있었고, 몇 년 주기로 별똥 소나기가 떨어졌음을 알아 냈다. 우리는 고려 시대의 별똥 기록을 두개로 나누어 별똥비의 세기가 어떤 진화를 하는지는 연구하였다. 7월 27일에 나타난 별똥비는 그 세기가 줄어든 것을 알 수 있었다.

• Journal of Astronomy and Space Sciences
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• 제21권1호
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• pp.39-72
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• 2004

《삼국사기》, 《고려사》, 《조선왕조실록》, 《승정원일기》 등 정통 한국 사서 원전에 수록되어 있는 천문관측 자료에서 별똥비와 별똥 소나기 기록을 검색하여 천문학적인 검토를 거쳐 그 목록을 작성하였다. 한국 사서에 나오는 별똥비 기록은 현재 국제 학계에 1958년 Imoto와 Hasegawa가 영문으로 발표한 논문이 표준이 되고 있는데, 이 문헌은 주로 1917년에 조선총독부에서 주관한 연구과제의 일환으로 일본인 관구리길가 작성한 보고서를 바탕으로 하고 있다. 그가 만든 목록은 날짜나 원전 인용 상의 오류를 상당히 포함하고 있으므로 본 연구에서는 한국의 정사서 원전을 검색하여 철저한 고증을 거쳐 수정되고 확장된 별똥비 및 별똥 소나기 목록을 작성하였다. 그 결과 지난 2천년 동안 한국의 역사서에는 별똥 소나기가 25번, 센별똥비가 4번, 보통 별똥비가 5번 기록되어 있었다. 그 가운데 일부는 사자자리 별똥비, 페르세우스 별똥비, 핼리혜성의 의해 생기는 물병자리-/sub n/ 별똥비와 오리온자리 별똥비 등에 속한 것으로 보이는 것이 있었으나, 상당히 많은 기록들은 이에 속하지 않았다. 본 연구에서 제시한 목록은 추후 많은 천체물리학적 연구에 유용할 것이다.

• 천문학논총
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• 제33권2호
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• pp.9-19
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• 2018

We investigate the life of Lee Cheon (1376-1451) who was closely connected with astronomy during the reign of King Sejong of the Joseon dynasty. Lee Cheon is widely regarded as one of the outstanding scientists of King Sejong's period. However, his contributions to the development of the astronomy during the period have not been enlightened. Based on the historical records on the life and achievements of Lee Cheon, mainly referring to the Joseonwangjosillok (Annals of the Joseon Dynasty), we address three important points. First, Lee Cheon was a distinguished administrator who filled various government posts. Second, he was a supervising engineer in public works and metal smelting during his position in military. Third, he was a scientific technician and manufactured precision equipment such as the metal movable type sets. By virtue of these aspects, Lee Cheon was taken into confidence by King Sejong on the Ganui-dae project (i.e., manufacture various astronomical instruments and construct their platform in order to make a calendar suitable for Joseon). During the period of this project, Lee Cheon not only supervised the construction of the Ganui (simplified armillary sphere) and Ganui-dae (platform for astronomical instruments) but also participated in the production of the astronomical instruments such as Gyupyo (Gnomon) and Honcheonui (Armillary Sphere). In conclusion, we regard Lee Cheon as one of the astronomers who led a great advance in astronomy during King Sejong's era.

• 천문학논총
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• 제31권3호
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• pp.57-63
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• 2016

We summarize our preliminary study on the research cooperation method in the astronomy field between Republic of Korea (South Korea) and Democratic People's Republic of Korea (North Korea). To investigate the recent astronomical activities of North Korea, we have surveyed the published records of research papers and international collaborations associated with North Korean astronomers. We found only 4 astronomical papers among the identified 260 SCI papers related to North Korean researchers for the past 11 years. North Korean astronomers had very few interactions with the international astronomical society before rejoining IAU in 2012. Recently, North Korea made several astronomical research exchanges with China and Netherlands. They seemed to attend several international conferences and present their research results. We have studied possibilities to establish international networks to encourage the cooperation between South and North, and suggest to start collaboration in the historical astronomy. The collaboration can be expanded gradually to other fields in astronomy. There are many obvious political difficulties to have interactions with North Koreans. However, it will be necessary to make a long-term plan considering the reunification.

• 천문학논총
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• 제39권1호
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• pp.13-26
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• 2024

The armillary sphere, an astronomical observation device embodying the Orbital Heaven Theory of the Later Han Dynasty in China, holds both historical and scientific significance. It has been produced in various forms by many individuals since its inception in the era of King Sejong in the Joseon Dynasty. A prominent figure in this field was Nam Byeong-cheol (南秉哲, 1817-1863), known for his work 'Uigijipseol' (儀器輯說), published in 1859, which detailed the history, production methods, and usage of the armillary sphere. This text particularly highlights 21 applications of the armillary sphere, divided into 33 measurements, covering aspects like installation, time, and positional measurements, supplemented with explanations of spherical trigonometry. Despite numerous records of the armillary sphere's design during the Joseon Dynasty, detailed usage information remains scarce. In this study, the 33 measurements described in 'Uigijipseol' (儀器輯說) were systematically classified into six for installation, nineteen for position measurement, seven for time measurement, and one for other purposes. Additionally, the measurement methods were analyzed and organized by dividing them into the ecliptic ring, moving equatorial ring, and fixed equatorial ring of the armillary sphere. In other words, from a modern astronomical perspective, the results of schematization for each step were presented by analyzing it from the viewpoint of longitude, right ascension, and solar time. Through the analysis of Nam's armillary sphere, this study not only aims to validate the restoration model of the armillary sphere but also suggests the potential for its use in basic astronomical education based on the understanding of the 19th-century Joseon armillary sphere.

• 천문학논총
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• 제8권1호
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• pp.153-161
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• 1993

We analyze 211 data of the daily sunspot observations during the period of January 4 to November 30 in 1993 and present the daily relative sunspot numbers. During 334 days of the period, the preliminary annual average of the relative sunspot numbers is found to be 61.8 based on 27.1 distinct spots in a single group for 3.7 spot groups. According to the appearance of 203 spot groups, our analysis shows that the mean life time of spot group is about 1 day and 15.5 hours. Our records show that more number of sunspots have appeared in the southern hemisphere than in the northern hemisphere by some 2%, indicating that the solar activities of the northern and southern hemisphere are much the same during the period.