간행물
천문학논총 KCI 등재 Publications of the Korean Astronomical Society
- 발행기관 한국천문학회
- 자료유형 학술지
- 간기 연3회
- ISSN 1225-1534 (Print)2287-6936 (Online)
- 수록기간 1984 ~ 2024
- 주제분류 자연과학 > 천문학 자연과학 분류의 다른 간행물
- 십진분류KDC 440DDC 520
권호리스트/논문검색
Volume 39 Issue 3 (2024년 12월) 2건
1.
2024.12
구독 인증기관 무료, 개인회원 유료
In March 2022, Wongu-ilyeong, a globe-like sundial made during the 19th century in the Joseon Dynasty, was repatriated from the United States through the efforts of the Korea Heritage Service and the Overseas Korean Cultural Heritage Foundation. This sundial has a total height of about 228 mm, and has time lines and a T-shaped gnomon on its spherical surface with a diameter of approximately 112.2 mm. This sundial is known to have been made by Sang Jik-Hyeon (尙稷鉉, 1849–?), as he carved his seal and the manufacturing date onto its spherical surface. This study investigated Sang, Jik-Hyeon's records from royal governmental literature, and also analyzed the structure of Wongu-ilyeong to understand its usage. We restored the Wongu-ilyeong’s design drawing and manufactured a prototype, with which we measured daytime hours in Jeju, Daejeon, and Seoul. The experimental measurements from three cities showed that the time accuracy of the Wongu-ilyeong, whose minimum time scale is 15 minutes, could be measured within ±7.5 minutes. Wongu-ilyeong is a very rare type of sundial-relic in Korea and overseas, and it is considered to have significant value in the history of science and technology.
4,500원
2.
2024.12
구독 인증기관 무료, 개인회원 유료
We see that the method of calculating the moon's position in the celestial sphere is little different from the method currently used. Currently, an elliptical model is used, while Sechoyuhwi and Chongzhen Lishu(崇禎曆書) use a four-epicycles model descibed in Lixiang Kaocheng(曆象考成) when calculating the equations of the Moon. The equation of center( EoC) calculated in this way has little difference from the currently calculated EoC. Considering the four-cycles model, the EoC occurs due to the center difference of the moon's orbit. The evection and variation occur when the sun exerts gravitational perturbation on the moon's orbit, and those are expressed as the 2nd and 3rd equations. However, when calculating the moon's position, Sechoyuhwi and Chongzhen Lishu used the apparent solar time. therefore these almanacs deal with another equation which is not the same as the 4th equation described as the equation of annual inequality. Furthermore these calendars consider the longitude reducing when the longitude along the lunar path in the celestial sphere is converted to that along the ecliptic. In this case the same as the 5th equation described as the equation of reduced ecliptic is corrected. When the ecliptic latitude were calculated, these calendars have considered the latitude evection of the lunar inclination to the ecliptic with the two-cycles model. At the time when Sechoyuhwi was written, Joseon’s lunar position tracking was at the highest level before Newton knew how to do it.
7,700원
