• 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.25 no.4
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• pp.155-165
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• 2010

In this study, we investigate the changes in the equatorial lodge degrees and polar distance degrees of determinative stars in the ancient Chinese archives. Confirmed is the fact that the coordinate values of those determinative stars defined in B.C. 104 had been used until the 8th century but were modified by the observations of Li Chunfeng (李淳風) in the early 7th century and Yixing (一行) in 723 A.D. The results of this study are compared with those in History of Chinese Astronomical Observations of Pan Nai. By applying the results of comtemporary astrodynamical calculations, their reliability is checked, and the corrected catalogues of Shi Shi (石氏) and Yixing are provided. The positional accuracy of those observations is estimated to be one degree.

• Journal of Astronomy and Space Sciences
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• v.26 no.3
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• pp.375-402
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• 2009

Korean historical constellations and their names are similar to Chinese ones. Although Korean historical astronomy is influenced by China, they have distinct differences in each shape and names of the constellations. We, therefore, compare Bocheonga (步天歌) of the early Joseon dynasty (朝鮮, $1392{\sim}1910$) preserved in Gyujanggark (奎章閣) with that of the Sui dynasty ((隋代, $581{\sim}618$ of China written by Wang Ximing(王希明) in terms of star charts and descriptions of the contents. We find out that the two books are partly different all over the books. First, there are definite differences in preface, three area of constellations (三垣) in the heaven, and the description of the Milky Way. Second, some of constellations show different in shape, the number of stars. Especially connecting pattern in some constellations shows different in each other. Third, Joseon Bocheonga describes their colors for some stars. These mean that Joseon has a unique tradition of star maps unlike Chinese one. We also summarize the differences and distinctive characteristics of Joseon star charts compared with Chinese ones.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.1
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• pp.83.3-83.3
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• 2019

New high-resolution spectra and multi-band photometric data of BS Cas were obtained at the Bohyunsan Optical Astronomy Observatory in 2018 and at the Jincheon Station of the Chungbuk National University Observatory in 2011, respectively. We measured the radial velocities (RVs) for both components, and the effective temperature of the more massive star was determined to be $6262{\pm}56K$. In addition, historical light curves showed strong time-dependant light variations at the total eclipse. These variations were modeled by a cool spot on the more massive component. Finally, the physical parameters of BS Cas by a simultaneous analysis of our RV curves with the photometric light curves were presented. Individual masses and radii of both components were deduced as $M_1= 0.59{\pm}0.07M_{\odot}$, $M_2=1.47{\pm}0.15M_{\odot}$, $R_1=0.94{\pm}0.03R_{\odot}$ and $R_2=1.47{\pm}0.05R_{\odot}$.

• Journal of The Korean Astronomical Society
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• v.47 no.6
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• pp.255-258
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• 2014

Using sunspot number data from 270 historical stations for the period 1981-2013, we investigate their personal reduction coefficients (k) statistically. Chang & Oh (2012) perform a simulation showing that the k varies with the solar cycle. We try to verify their results using observational data. For this, a weighted mean and weighted standard deviation of monthly sunspot number are used to estimate the error from observed data. We find that the observed error (noise) is much smaller than that used in the simulation. Thus no distinct k-variation with the solar cycle is observed contrary to the simulation. In addition, the probability distribution of k is determined to be non-Gaussian with a fat-tail on the right side. This result implies that the relative sunspot number after 1981 might be overestimated since the mean value of k is less than that of the Gaussian distribution.

• Korean Journal of Heritage: History & Science
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• v.56 no.4
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• pp.24-37
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• 2023

This study analyzes the materials and external characteristics of the Angbu-ilgu, a kind of scaphe sundial, which was newly designated as a Korean Treasure in 2022. The Angbu-ilgu Treasure is owned by three institutions - the National Palace Museum Of Korea, Gyeongju National Museum, and Sungshin Women's University Museum - and is similar as a twin in its material, size, outward appearance, as well as production techniques that include casting, silver inlays, and metal joints. The Three-Treasure Angbu-ilgu is made of brass in the ratio of 90.6: 6.0: 1.8 with Cu: Zn: Pb. This composition clearly differs from Treasure No. 845, an Angbuilgu which has a composition ratio of 82.2: 3.7: 11.8 with Cu: Zn: Pb. In this new Angbu-ilgu Treasure, the hemisphere's stand has four vertical pillars sculpted in a dragon pattern and bilateral wings carved in a cloud pattern on the pillars, which are joined to the hemisphere's horizontal ring with rivets and silver solders, respectively. The dragon-in-clouds pillar (雲龍柱) shows the most outstanding formative beauty of the various Angbu-ilgu pillars produced in the late Joseon Dynasty. It can be seen that the altitude of the north pole engraved on the Angbu-ilgu was made after 1713. Production is, however, actually estimated to have occurred close to the 19th century, the era of the Jinju Kang family, who were professional Angbuilgu makers. Hopefully, this study will lead to a historical science and technology review with modern scientific instruments analyzing the materials and external characteristics of the three Angbu-ilgus designated as a Korean Treasure in 2022.

• The Bulletin of The Korean Astronomical Society
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• v.43 no.2
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• pp.50-50
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• 2018

한국의 근현대 천문학은 조선시대 관상감의 명맥을 잇고 천문학의 현대화를 이루는 과정에서 역사적이고 문화적인 자료를 남겼다. 그 중 국립천문대를 거쳐 한국천문연구원에 이르기까지 주요 연구 결과물은 국가적 차원에서 보존해야 할 가치 있는 기록물들이다. 이들은 연구 환경변화의 주요 인물과 스토리까지 포괄하고 있으므로 그 과정에서 파생된 소산물도 체계적으로 조직화하여 대중에게 서비스할 필요가 있다. 이 기획 연구는 도큐멘테이션 전략과 사료 콘텐츠 세트 개발 방법론을 활용하여 한국 근현대 천문학 기록물을 수집하고 주제별로 재가공하는 절차를 제시한다. 도큐멘테이션 전략은 국내외에 산발적으로 분산된 한국 근현대 천문 사료의 유형과 지역 등 편중성을 가려내어 중복된 기록물은 걸러내고 희소성 높은 기록물을 선별하여 수집하는 방법론이다. 천문 사료 콘텐츠 세트는 한국천문학사의 주요 인물과 천문대 등 학술적, 문화적으로 가치 있는 주제를 중심으로 본(本) 기록물과 연관 기록물을 맥락적으로 관리 서비스할 수 있는 방법론이다. 이 연구를 통하여 초중등 교과 과정이나 유관 기관과 서비스를 연동하여 한국천문지식정보의 범용화와 천문 아카이브에 대한 대중의 접근 편의를 도모할 수 있을 것으로 기대된다.

• Publications of The Korean Astronomical Society
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• v.37 no.3
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• pp.49-57
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• 2022

In this study, we collected articles published in the Publication of the Korean Astronomical Society (PKAS) from 1984 to 2021, and performed quantitative analyses of their various aspects. PKAS is the journal where authors can publish research papers in Korean as well as English. It seems to have an advantage of the better accessibility to all people than other astronomy journals in English only. From 1984 to 2000, the number of articles published in PKAS has been steadily increased. From 2000, the number of published articles showed a tendency to decrease slightly every year. After 2010, the number of articles in PKAS has shown a sharp decline until now. Interestingly, in this period it is found that the topics published articles became various, in particular, many articles concerning historical astronomy began to be published. PKAS was selected as an accredited journal in 2018. This is a very positive situation, and we think the future direction of PKAS is encouraging. Considering these circumstances, the PKAS is suggested to reflect ideas of "interdisciplinary fusion" and "diversity" in publishing articles in the journal for its promising future.

• The Bulletin of The Korean Astronomical Society
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• v.46 no.2
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• pp.65.1-65.1
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• 2021

The Donggungilgi (東宮日記) is the daily records of the Siganwon (侍講院), which was a royal office in the Joseon dynasty that took charge of the education for the crown prince who dwelled in the Donggung (East Palace). This literature contains records of meteorological and astronomical observations as well as educational matters. The Sohyeon-Donggungilgi (昭顯東宮日記) includes records from 1625 to 1645, when Prince Sohyeon, the first son of King Injo (仁祖), was the crown prince. We investigate the records of solar halo observations in the Sohyeon-Donggungilgi. For consistency, we restrict our investigation to the period before the second Manchu invasion of Korea (i.e., 1625 to 1635). We extract 2,684 records and classify them into ten events according to the terms in their descriptions. The largest and smallest number of observation records are for the Hun (暈) and Geuk (戟) events (1,794 and 7 records, respectively). To verify what each event represents in modern atmospheric terms, we refer to historical documents of the Seoungwanji (書雲觀志, Treaties on the Bureau of Astronomy) and Cheonmundaeseong (天文大成, Great Achievements in Astronomy). We also calculate the solar altitude based on the observation hour and compare the descriptions to compute simulations provided by Arbeitskreis Meteore e.V.. We find that the descriptions of the Hun, Junghun (重暈), Yi (珥), and Baekhonggwanil (白虹貫日) events indicate a 22˚ halo, 22˚ and 46˚ halos, a parhelion, and a parhelic circle, respectively, Alternatively, we estimate that the Gwan (冠), Dae (戴), Bae (背), Li (履), and Gyohun (交暈) events describe arcs tangent to a 22˚ or 46˚ halo such as a upper or lower tangent arc, a circumzenithal arc, or a parry arc. We suggest that further studies are required for the Geuk event because the descriptions of this event differ from both documents referred to this study. In the sense that the number of observation records of the Geuk event is the smallest, however, this event may describe a rare phenomenon. We believe that this work will contribute to the study of historical records of solar or lunar halos.

• Publications of The Korean Astronomical Society
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• v.31 no.3
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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.