• Journal of Astronomy and Space Sciences
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• v.23 no.1
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• pp.71-90
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• 2006

This study is about , which constitutes Honcheonui(an armillary sphere) put of $\ulcorner$Uigijipseol$\lrcorner$ (Volume I) together with and -dealt with earlier than this subject. The study's construction on the text of is organized into 15 categories, including installation, observations, instructions for use, astronomical theories and formulas, etc. This study provides easy-to-understand illustrations of the figures shown in the original and contains detailed descriptions of the related calculation procedures. In the 'Instructions for Use of Honcheonui' discussed here, the readers are introduced to astronomical computation systems, mainly based on spherical trigonometry and proportional methods. The section also provides systematic and detailed reviews of astronomical theories and calculation procedures, allowing you to assess the level of astronomy knowledge at that time.

• Publications of The Korean Astronomical Society
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• v.33 no.2
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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.

• Journal of Engineering Education Research
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• v.5 no.1
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• pp.77-84
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• 2002

The 18th century Joseon(朝鮮) science philosopher Hong Dae-Yong(洪大容, 1731-83) tried to create his own scientific system, while partially keeping the Eastern view of nature and accepting Western science and technology. Most of all, he confirmed that Western science and technology was based on mathematical principles and accurate observation and wrote a math book, [Juhaesuyong(籌解需用)]. Therefore, we have good reason to call him a mathematician. He produced so many achievements that he can be considered a natural scientist in the late Joseon era; he accepted the Eastern view of nature critically and sometimes refused it. He also suggested new and various scientific thoughts, including an infinite universe theory, on the basis of Western scientific thought. Hong Dae-Yong emphasized the importance of practice. He understood the principle of the Western Honcheonui(渾天儀) and manufactured an alarm clock with a craftsman's help. He was an excellent engineer and he set a personal observatory. Considering the level of scientific technology at that time, it is reasonable to regard Hong Dae-Yong as a 'scientific technologist in the 18th century Joseonera', well equipped as a mathematician, a natural scientist, and an engineer. In conclusion, it is with 'mathematical thinking, creative conception, and practical activities' that Hong Dae-Yong maintained throughout his life that we can set a guide to produce excellent Korean scientific technologists and engineers in the 21st century.