• Journal of The Korean Astronomical Society
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• v.47 no.3
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• pp.115-122
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• 2014

The New Vacuum Solar Telescope (NVST) is a 1-meter vacuum solar telescope that aims to observe the fine structures of active regions on the Sun. The main tasks of the NVST are high resolution imaging and spectral observations, including the measurements of the solar magnetic field. The NVST has been collecting more than 20 million FITS files since it began routine observations in 2012 and produces maximum observational records of 120 thousand files in a day. Given the large amount of files, the effective archiving and retrieval of files becomes a critical and urgent problem. In this study, we implement a new data archiving system for the NVST based on the Fastbit Not Only Structured Query Language (NoSQL) database. Comparing to the relational database (i.e., MySQL; My Structured Query Language), the Fastbit database manifests distinctive advantages on indexing and querying performance. In a large scale database of 40 million records, the multi-field combined query response time of Fastbit database is about 15 times faster and fully meets the requirements of the NVST. Our slestudy brings a new idea for massive astronomical data archiving and would contribute to the design of data management systems for other astronomical telescopes.

• Publications of The Korean Astronomical Society
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• v.39 no.1
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• pp.1-12
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• 2024

In this study, we investigated the time signal devices of Deungnu (circa 1270) and Gungnu (1354), the water clocks produced during the Yuan Dynasty (1271-1368). These clocks influenced Heumgyeonggaknu (1438) of the Joseon Dynasty (1392-1910), exemplifying the automatic water clocks of the Yuan Dynasty. Deungnu, Gungnu, and Heumgyeonggaknu can be considered as automatic mechanical clocks capable of performances. The Jega-Yeoksang-Jip (Collection of Calendrical and Astronomical Theories of Various Chinese Masters) contains records of Deungnu extracted from the History of the Yuan Dynasty. We interpreted these records and analyzed reproduction models and technical data previously produced in China. The time signal device of Deungnu featured a four-story structure, with the top floor displaying the four divine constellations, the third floor showcasing models of these divinities, the second floor holding 12-h jacks and a 100-Mark ring, and the first floor with four musicians and a 100-Mark Time-Signal Puppet providing a variety of visual attractions. We developed a 3D model of Deungnu, proposing two possible mechanical devices to ensure that the Time-Signal Puppet simultaneously pointed to the 100-Mark graduations in the east, west, south, and north windows: one model reduced the rotation ratio of the 100-Mark ring to 1/4, whereas the other model maintained the rotation ratio using four separate 100-Mark rings. The power system of Deungnu was influenced by Suunuisangdae (the water-driven astronomical clock tower) of the Northern Song Dynasty (960-1127); this method was also applied to Heumgyeonggaknu in the Joseon Dynasty. In conclusion, these automatic water clocks of East Asia from the 13th to 15th centuries symbolized creativity and excellence, representing scientific devices that were the epitome of clock-making technology in their times.

• Journal of The Korean Astronomical Society
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• v.49 no.4
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• pp.163-173
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• 2016

In this paper, we study the lunar eclipse records in the Goryeosa (History of the Goryeo Dynasty), an official history book of the Goryeo dynasty (A.D. 918 - 1392). In the history book, a total of 228 lunar eclipse accounts are recorded, covering the period from 1009 to 1392. However, we find that two accounts are duplications and four accounts correspond to no known lunar eclipses around the dates. For the remaining lunar eclipses, we calculate the magnitude and the time of the eclipse at different phases using the DE406 ephemeris. Of the 222 lunar eclipse accounts, we find that the minimum penumbral magnitude was 0.5583. For eclipses which occurred after midnight, we find that some accounts were recorded on the day before the eclipse, like the astronomical records of the Joseonwangjosillok (Annals of the Joseon Dynasty), while others were on the day of the lunar eclipse. We also find that four accounts show a difference in the Julian dates between this study and that of Ahn et al., even though it is assumed that the Goryeo court did not change the dates in the accounts for lunar eclipses that occurred after midnight. With regard to the contents of the lunar eclipse accounts, we confirm that the accounts recorded as total eclipses are accurate, except for two accounts. However, both eclipses were very close to the total eclipse. We also confirm that all predicted lunar eclipses did occur, although one eclipse happened two days after the predicted date. In conclusion, we believe that this study is very helpful for investigating the lunar eclipse accounts of other periods in Korea, and furthermore, useful for verifying the calendar dates of the Goryeo dynasty.

• Journal of Astronomy and Space Sciences
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• v.23 no.1
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• pp.55-70
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• 2006

There are many astronomical records of comets in Korean history books. We collected those of the comet that appeared in the winter of the year 1664. These records were written in Daily Reports of the Royal Observatory on Astronomical Events (星變測候單子), Final Reports of the Royal Observatory on An Astronomical Events (天變謄錄), the Daily Records of the Royal Secretariat of the Joseon Dynasty (承政院日記), and the Chronicle of the Joseon Dynasty (朝鮮王朝實錄). We used the Olbers' method for determination of preliminary orbit of the comet, and compared the result with the previous researches. In the Oblers' method the orbit is assumed to be parabolic (e=1). We obtained the following orbital elements: perifocal distance q=1.07\pm0.008AU, perifocal passage time $T=2329165.50\pm0.72$ days, argument of the perifocus $\omega=318^{\circ}.2\pm2^{\circ}.29$, longitude of ascending node $\Omega=85^{\circ}.23\pm2^{\circ}53(J1665)$(J1665), inclination $i=160^{\circ}.28\pm1^{|circ}.56$.

• Publications of The Korean Astronomical Society
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• v.25 no.4
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• pp.129-139
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• 2010

The Cowherd Star and the Weaving Maid Star have been famous stars in East Asian countries. Nowadays Altair is defined to be the Cowherd Star in public materials including science books, mass media, public outreach programs, and movies played in public planetariums and science museums. However, in astronomical books and star-charts in history, the Cowherd Big Star (牽牛大星) has been known to be Dabih or $\beta$ Cap in the constellation Capricorn, and the asterism Cowherd consists of six stars including Dabih. Since the same title is given to the different objects simultaneously, considerable misunderstanding and confusion among the public have occurred. In this paper we consider this problem in two aspects. One aspect is which star has been defined to be the Cowherd Star in ancient literatures; the other is which stars were regarded as the Cowherd or the Cowherd Star in the historical records of occultation or conjunction in History of Koryo, Annals of the Choson Dynasty, and Daily Records of Royal Secretariat of the Choson Dynasty. As a result, we see that Altair has been regarded as the Cowherd Star in folklore and literature, but Dabih has been defined to be the Cowherd Big Star in astronomical works. An explanation proposed by previous researchers on the reason why such double meanings have been appeared is introduced. In the explanation, the fact that the Altair was defined as the Cowherd Star in ancient times had not been handed over properly, and the name of Cowherd was later put to the Dabih and its surrounding five stars to form one of 28 lunar lodges. Based upon these facts, we suggest the following ideas: (1) Altair should be introduced to be the Cowherd Star in public-friendly programs, and Dabih should be noticed to be the Cowherd Big Star in the field of history of astronomy. Dabih should be added as the astronomical Cowherd Big Star in academic books such as a dictionary of astronomical terminology. (2) The Korean pronunciation for Altair should be al-tear instead of al-tairu in accordance with the definition in the astronomical terminology dictionary compiled by the Korean Astronomical Society.

• Publications of The Korean Astronomical Society
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• v.17 no.1
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• pp.23-40
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• 2002

The spatial distribution of meteoroids or cometary debris along the orbit of the Earth is investigated by analyzing the meteoric records in the Chronicle of the Koryo dynasty (918-1392) which is called Koryosa. Sporadic meteors in this period show the seasonal variation in number, which is similar to the current meteors. We also found that there are a few spikes showing large accumulation of records around the same dates. We regard these spikes as meteor showers in the Koryo period. We compared the dates of meteor showers with those compiled from the historical records around the world including Korea, Japan, China, Arab, and European countries. We discovered three prominent showers and four weak showers. The prominent ones are the Leonids, the Perseids, and the Aquarids and the Orionids pair. The last pair is the remnants of Halley's comet. The astronomical records written in the history book of the Koryo dynasty are turned out to be accurate and written in a steady manner. We can also see that those records can be useful to contribute the development of modern astronomy and astrophysics.

• Publications of The Korean Astronomical Society
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• v.31 no.3
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• pp.77-85
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• 2016

We study the manufacturers of the astronomical instruments invented as part of the so-called Ganui-Dae (astronomical platform) project in the reign of King Sejong (1418-1450) of the Joseon dynasty. The main purpose of this project was to compile the Chiljeongsan-Naepyeon, a Korean calendar, that lasted for 5.5 years from 1432 to 1438. Through this project, a total of 17 astronomical instruments such as the armillary sphere, celestial globe, and auto-striking clepsydra were developed. It is generally known that most of them were manufactured by Lee Cheon (李蕆, 1376-1451) and Jang Yeong-Sil (蔣英實, fl. 1423-1442). In this study, we investigate the accounts of the Veritable Records of King Sejong, Munjong, and Sejo, focusing on the inscription written out to memorize the completion of the Ganui-Dae project. We found that at least 12 persons took part in manufacturing the astronomical instruments of the Ganui-Dae project. Lee Cheon was involved in the production of four instruments, while Jang Yeong-Sil was involved in two; therefore, it seems that the achievement of Jang Yeong-Sil was overestimated. We also found that Jeong Cho (鄭招, ?-1434) was a scientist and Lee Cheon was an engineer in the early phase of the Ganui-Dae project, while King Sejong and Yi Sun-Ji (李純之, 1406-1465) played major role in the late phase. According to our study, King Sejong and Yi Sun-Ji were involved in the production of at least seven and five instruments, respectively. In conclusion, we believe that this study will be helpful to understand the practical manufacturers of the astronomical instruments invented during the Ganui-Dae project in the Joseon dynasty.

• Publications of The Korean Astronomical Society
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• v.20 no.1 s.24
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• pp.85-95
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• 2005

We collected eleven large astronomical catalogues, which include 2MASS, USNO B1.0, GSC 2 catalogues and so on. Most of these catalogues are the frequently used by astronomers for all sorts of applications. But the researches are faced with the problem of accessing these databases because these catalogues contain from tens millions up to thousands of millions of records. So we developed a web application system to manage these large catalogues, the main purpose of the web application is to allow a powerful and efficient querying activity on these catalogues through internet by using a simple web interface. User could retrieve the query result in variety of formats including plain text, HTML, Microsoft Excel format (XLS), and VOTable. Furthermore, user also could display and analyze result graphically by using a powerful interactive visualization tools named VOPlot which was developed by the Virtual Observatory-India (VOI) project.

• Publications of The Korean Astronomical Society
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• v.26 no.4
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• pp.147-157
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• 2011

I found evidence that Kim Y$\breve{o}$ng (金泳, 1749-1817) is the author of the Korean Poch'$\breve{o}$n'ga with New Charts published in 1792 by the Astronomical Bureau of the Chos$\breve{o}$n dynasty. I reconstructed a history of Kim Y$\breve{o}$ng from various literature remained in other persons' anthologies and governmental records. My findings on the author and publication year can help to solve the problem on the origin of star charts in the Poch'$\breve{o}$n'ga with New Charts. I also considered the changes of Chinese Bu-Tian-Ge and their star charts after Chongzhenglishu (崇禎曆書). I found that the new charts in the book of Huantiantushuo published by Li Mingche (李明徹, 1751-1832) in 1819 are approximately the same to those in the Poch'$\breve{o}$n'ga with New Charts by Kim Y$\breve{o}$ng in 1792.

• The Bulletin of The Korean Astronomical Society
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• v.43 no.2
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• pp.49.2-49.2
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• 2018

한국천문연구원에서 "동아시아 천문아카이브 구축을 위한 기획연구"의 일환으로 2018년 4월부터 6월까지 수행한 천문사료 연구 계획을 소개하고자 한다. 이 연구의 목적은 정사 및 개인문집에 수록된 방대한 한국의 천문기록자료를 집대성하는 것이다. 우선적으로 고려사, 조선왕조실록, 승정원일기 등의 정사에 수록된 천문 기록들을 일정한 형식으로 수집하려고 한다. 이들을 다른 관찬 문헌 및 사찬 문집 등과 비교 연구를 통해 e-science 기반 자료로 활용하고자 한다. 1 단계 총 5년간의 연구기간을 통해서 순차적으로 open science platform 형식의 천문 아카이브로 제공할 계획이다.