• Title/Summary/Keyword: lunar occultation

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AT WHAT TIME A DAY BEGINS IN THE KOREAN HISTORY? (한국사에서 하루의 시작은 언제부터인가?)

  • Ahn, Sang-Hyeon;Park, Jong-Woo
    • Journal of Astronomy and Space Sciences
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    • v.21 no.4
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    • pp.505-528
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    • 2004
  • We have reproduced the records of lunar occultation recorded in the History of Three Kingdoms(삼국사기), the History of the Koryo Dynasty (고려사), the Annals of the Choson Dynasty (朝鮮王朝實錄), the Daily Records of Royal Secretariat of the Choson Dynasty (승정원일기), and obtained the epochs of their realizations. We analysed these results to understand how the system of hours had been kept and when a day began. During most of the periods encompassed by these annals, the 12 double hours(12진각법) and the system of 100 divisions of the day (백각법) had been used when the lunar and the solar eclipses were calculated by royal astronomers. In these systems, the starting point of a day is midnight. On the other hand, the five watch system of hours (경점법), in which a night is divided into five watches, was also used. In this system, a day begins at the sunrise. We found that the traditional twilight, called dusk and dawn (혼명) and used in the east Asian countries, largely corresponds to the nautical twilight in modern concepts. This fact means that the Korean expressions and words for time system in every day life had originated form the five watch system of hours. We pointed out that the sunrise and sunset were convenient boundary lines to ancient astronomers, as well as to farmers in the agricultural society. Our results can be used to determine the exact epoch of each astronomical record in chronicles.

THE STRUCTURES AND POSSIBLE SOURCES OF PRESERVICE ELEMENTARY TEACHERS' MENTAL MODELS ABOUT MOON PHASES (달의 위상변화에 대한 예비 초등교사의 가능한 정신모형)

  • Oh, Jun-Young;Kang, Yong-Hee;Yoo, Kye-Hwa
    • Journal of Astronomy and Space Sciences
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    • v.22 no.3
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    • pp.311-328
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    • 2005
  • This study was to understand the components that influence preservice elementary teachers' mental models about 'astronomical phenomena' such as the Seasons of the year, and the Lunar Phases of the month. We selected university of education students among whom 23 were in the second you. The data collected from the paper-pencil test and individual interview with students. The results of this study show that the students had apparent synthetic Mental models, and that the distance theory, and occultation theory had most important effects on their Mental Models. It can be said that preservice elementary teachers' initial mental models of the' astronomical phenomenon' have their origin in their belief sets (specific theory) related to 'astronomical phenomenon', on the basis of which they can interpret their observations and cultural information with the constraints of a naive framework of physics. The structures and possible sources of their mental models for overcoming these synthetic mental models were also discussed.

DECIPHERING THE DOUBLE MEANINGS OF THE COWHERD STAR (견우성의 이중적 의미에 대한 해석)

  • Ahn, Sang-Hyeon;Kim, Dong-Bin;Lee, Yong-Sam;Song, Doo-Jong
    • 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.