• Journal of Astronomy and Space Sciences
• /
• 제34권2호
• /
• pp.161-170
• /
• 2017

In this study, the characteristics of a horizontal sundial from the Joseon Dynasty were investigated. Korea's Treasure No. 840 (T840) is a Western-style horizontal sundial where hour-lines and solar-term-lines are engraved. The inscription of this sundial indicates that the latitude (altitude of the north celestial pole) is $37^{\circ}$ 39', but the gnomon is lost. In the present study, the latitude of the sundial and the length of the gnomon were estimated based only on the hour-lines and solar-term-lines of the horizontal sundial. When statistically calculated from the convergent point obtained by extending the hour-lines, the latitude of this sundial was $37^{\circ}$ $15^{\prime}{\pm}26^{\prime}$, which showed a 24' difference from the record of the inscription. When it was also assumed that a convergent point is changeable, the estimation of the sundial's latitude was found to be sensitive to the variation of this point. This study found that T840 used a vertical gnomon, that is, perpendicular to the horizontal plane, rather than an inclined triangular gnomon, and a horn-shaped mark like a vertical gnomon is cut on its surface. The length of the gnomon engraved on the artifact was 43.1 mm, and in the present study was statistically calculated as $43.7{\pm}0.7mm$. In addition, the position of the gnomon according to the original inscription and our calculation showed an error of 0.3 mm.

• 천문학논총
• /
• 제28권3호
• /
• pp.55-63
• /
• 2013

동아시아에서 규표는 가장 전통적인 천문의기 중 하나였다. 그럼에도 불구하고 고전적 규표는 표의 수직 설치와 유지가 어렵고, 눈금의 시작점이 모호하였으며, 무엇보다도 태양의 표 그림자가 퍼져 관측의 정밀성이 떨어졌다. 이러한 고전적 규표의 단점을 해결하고자 하는 노력의 결과물로 13세기에 횡량형 규표가 개발되었다(민병희 등, 2011). 횡량형 규표는 영부를 사용하여 선명한 횡량 그림자를 얻었다. 영부를 통해 얻은 횡량 그림자는 예리하여 관측의 모호성이 없으며, 동시에 태양의 중심 위치를 관측하는 최적의 천문의기이었다. 대규표는 횡량을 설치하였는데, 이 횡량의 크기는 길이 6자(124.2 cm), 직경 3치(6.21 cm)이었다. 표 기둥 위에 횡량을 올린 것을 얼이라고 하고, 이 얼을 수직으로 설치하는 것이 횡량형 규표의 핵심이었다. 삼점현추법을 사용하여 얼을 규에 수직으로 세울 수 있었다. 삼점현추법을 사용하기 위해 횡량은 길이 5치(10.35 cm), 직경 2푼(4.14 mm)의 철사 3개를 이용하고 있다. 삼점현추법은 단지 횡량을 정렬하는데 만 필요한 것이 아니고, 횡량을 점검하고 진단하는데도 활용되었다. 횡량의 개발은 태양 중심의 그림자길이를 측정하는 천문학적 이점과 더불어 규표의 대형화를 가능하게 하였다. 규표의 적절한 건설 공정과 삼점현추법을 적용하면 이상적으로는 높이에 무관하게 얼을 수직하게 설치할 수 있었기 때문이다. 얼의 크기가 높아질수록 결과적으로 눈금의 분해능을 증가시킬 수 있기 때문에(이용삼 등, 2006) 관측의기의 성능을 향상시킬 수 있었다.

• 천문학논총
• /
• 제26권3호
• /
• pp.129-140
• /
• 2011

In this paper, we have studied Sogyupyo (小圭表, small noon gnomon) of the Joseon dynasty. According to the Veritable Records of King Sejong (世宗, 1418 - 1450), Daegyupyo (大圭表, large noon gnomon) with a height of 40-feet [尺] was constructed by Jeong, Cho (鄭招) and his colleagues in 1435, and installed around Ganuidae (簡儀臺, platform of Ganui). On the contrary, the details of Sogyupyo are unknown although the shadow length measurements by Daegyupyo and Sogyupyo are found on the Veritable Records of King Myeongjong (明宗, 1545 - 1567). By analysing historical documents and performing experiments, we have investigated the construction details of Sogyupyo including its development year, manufacturer, and installation spot. We have found that Sogyupyo would be manufactured by King Sejong in 1440 and placed around Ganuidae. And Sogyupyo would be five times smaller than Daegyupyo, i.e., 8-feet. On the basis of experiments, we suggest that although it is smaller, Sogyupyo was equipped with a bar [橫梁] and a pin-hole projector [影符] like Daegyupyo in order to produce the observation precision presented in the Veritable Record of King Myeongjong.

• Journal of Astronomy and Space Sciences
• /
• 제23권3호
• /
• pp.289-302
• /
• 2006

조선초기 세종대에 제작하여 사용한 규표를 복원하기위해 '세종실록'을 비롯한 조선시대의 문헌자료를 수집하여 원리와 구조를 분석하였다. 그리고 이를 근거로 1/10로 축소 모형을 제작하고 설계도를 완성하였다. 규표의 구조는 규(圭), 용표(龍表), 횡량(橫梁), 또는 들보), 받침대로 구성되어 있다. 수직으로 세운 막대인 용표의 그림자가 수평으로 놓인 규면에 맺힐 때 눈금을 읽으면 된다. 이때 그림자 중심에 태양의 상을 맺히게 하는 영부를 사용하여 정밀하게 측정한다. 영부는 가운데 바늘구멍을 뚫은 작은 동판을 사용하여 바늘구멍 사진기와 샤임프러그 원리를 이용하여 태양의 영상을 맺히도록 한다.

• 천문학논총
• /
• 제27권2호
• /
• pp.29-37
• /
• 2012

In this paper, we study the structure of the Daegyupyo (大圭表, Large Gnomon) of the early Joseon dynasty. A Gyupyo (圭表, Gnomon that is Guibiao as pronounced in Chinese) is composed of a Pyo (表, Biao as pronounced in Chinese) making a shadow and a Gyu (圭, Gui as pronounced in Chinese) measuring its length. It is known that the Daegyupyo with the 40-feet height was constructed between the sixteenth to seventeenth year of the King Sejong reign (1444 - 1445) on the basis of the record of Yuanshi (元史, the History of the Yuan Dynasty). By analyzing historical documents such as Joseonwangjosillok (朝鮮王朝實錄, the Annals of the Joseon Dynasty), Yuanshi, and Jegaryeoksangjip (諸家曆象集, a work written by Sunji Lee), we found a possibility that the Ji (池, a pond) on the Gyu was located in the north side of the Pyo. This structure is different from that in previous studies, but is in a good agreement with that of the 40-feet Guibiao remaining in Dengfeng (登封) of China. Regarding to the Hoengyang (橫梁, cross-bar), we suggest that it was set up by double 5-feet supporting arms apart from the north tip of the Pyo in the radial direction. The 3:4:5 ratio in a rectangular triangle was used to place the Heongyang on the top of the Pyo at a distance of 4-feet (3-feet) in the vertical (horizontal) direction. We also discuss the structural problem when the Hoengyang is positioned apart from the top of the Pyo by supporting arms. In conclusion, we think that this study should be useful in restoring the Daegyupyo of the Joseon dynasty.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
• /
• 한국우주과학회 1998년도 한국우주과학회보 제7권1호
• /
• pp.32-32
• /
• 1998

No Abstract.See Full-text

• Journal of Astronomy and Space Sciences
• /
• 제27권2호
• /
• pp.161-172
• /
• 2010

In this paper, we investigate the sundials made by the Kang Family of Jinju in the later period of the Joseon dynasty in terms of their characteristics, functions and the manufacturing technique. One of the characteristics of these sundials is that the value of polar height (i.e., the latitude of Seoul), the name of manufacturer, 24 seasonal subdivisions and so forth are written on the surface. In particular, polar height is expressed as '$37^{\circ}$ 39' 15"' in all 12 sundials examined in this study. To investigate the manufacturing technology in terms of astronomy, we analyze the positions of gnomon and of the lines corresponding to 24 seasonal subdivisions (season lines) and to each hour (hour lines). To verify the accuracy of the positions, we use a planar projection method. That is, we obtain 2D images of the sundials using a camera or scanner, and compare these with astronomical calculations for the positions of gnomon and season/hour lines. We believe that this method will be very useful for the study of sundials preserved elsewhere.

• 천문학회보
• /
• 제41권1호
• /
• pp.51.4-52
• /
• 2016

이 논문에서는 "원사" "천문지" <경부>조의 기록을 바탕으로 조선시대 영부에 대해 연구하였다. 조선에서는 1435년과 1440년에 처음으로 대규표와 소규표가 제작되었으며, 이들은 모두 횡량을 가진 진화된 형태의 규표로써 영부를 사용하여 그림자길이를 측정하였다. 영부는 바늘구멍 장치로 Needham et al.에 의해 처음으로 그 모델이 제시되었지만, 구조적 측면에서 "원사"의 원문 내용과 차이를 보이고 있다. 이 연구에서는 조선시대 영부를 "원사"의 경부와 동일했을 것으로 가정하였으며, 이를 토대로 새로운 모델을 제시하였다. 바늘구멍을 통과하는 빛의 경로에 대한 분석을 통해 새 모델의 재원 중 "원사"에 명시되지 않은 영부 밑받침의 높이를 추정하였다.

• Journal of Astronomy and Space Sciences
• /
• 제32권4호
• /
• pp.395-401
• /
• 2015

We investigated the six remaining Yang-cheon-cheoks (量天尺), which were first described in the Veritable Record of King Sukjong (肅宗實錄). These woodblock sundials from Korea are structurally very similar to a Gyupyo (圭表, gnomon) or an altitude sundial and are light, compact, and portable. The front side of a Yang-cheon-cheok has two holes for styluses and several hour-lines. We compared the intervals of the hour-lines from the originating point of the stylus placement on all Yang-cheon-cheoks and found that two of the relics had the same hour-lines using the standard of the unit of 1 chon (寸). These two were actually the same sundial although the physical size was different. In spite of the lack of time accuracy, we hypothesize that various-sized Yang-cheon-cheoks were made and widely distributed throughout the public in the late Joseon Dynasty.

• Journal of Astronomy and Space Sciences
• /
• 제30권4호
• /
• pp.299-305
• /
• 2013

Ganui-Dae, built in the reign of King Sejong, Joseon Dynasty, is a comprehensive observatory. It has various instruments for observation and time signal such as Ganui, Gyupyo(Gnomon), water-hammering type Honui and Honsang, and so on. Studying on Ganui-Dae has been focused on its location, history, criterion, etc, so far. However, studying on its external form and construction method has been conducted insufficiently. This study suggests the model for restoration of Ganui-Dae. The model is based on the analysis about external form of Ganui-Dae in various antique maps, and its construction method in those days.