• 천문학회지
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• 제45권1호
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• pp.19-24
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• 2012

Microthermal fluctuations are introduced by atmospheric turbulence very near the ground. In order to detect microthermal fluctuations at Fuxian Solar Observatory (FSO), a microthermal instrument has been developed. The microthermal instrument consists of a microthermal sensor, which is based on a Wheatstone bridge circuit and uses fine tungsten filaments as resistance temperature detectors, an associated signal processing unit, and a data collection, & communication subsystem. In this paper, after a brief introduction to surface layer seeing, we discuss the instrumentation behind the microthermal detector we have developed and then present the results obtained. The results of the evaluation indicate that the effect of the turbulent surface boundary layer to astronomical seeing would become sufficiently small when installing a telescope at a height of 16m or higher from the ground at FSO.

• 천문학회보
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• 제36권2호
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• pp.85.2-85.2
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• 2011

A new infrared spectro-polarimeter was installed in 2008 onto the Solar Flare Telescope of NAOJ in the Mitaka headquarters. The Solar Flare Telescope had been operated previously as a filter-based magnetograph and obtained vector magnetograms of active regions with the Fe I 630.3nm line during 1992 - 2005. The aim of this new instrument is to measure the distribution of magnetic helicity over the whole Sun and for an extended period with high magnetic sensitivity in the infrared wavelengths. This spectro-polarimter is able to obtain polarizations in both photospheric and chromospheric layers. In order to take full Stokes profiles, we observe Fe I 1564.8 nm and He I 1083.0 nm lines (with the neighboring photospheric Si line) for the photospheric and chromospheric magnetic field vectors, respectively. The infrared detector of this instrument is a $640{\times}512$-pixel InGaAs camera produced by a Belgian company Xenics. The frame rate of the camera is 90 frames/sec. The 640-pixel row of this camera is set along the spectrograph slit of the polarimeter. Since the slit only covers the solar hemisphere, a full disk map is obtained by raster scanning the solar disk twice. A magnetic map is made of about $1200{\times}1200$ pixels with a pixel size of 1.8 arcsec. It generally takes 1.5 hours to scan the whole Sun. Although some issues on the instrument calibration still remain, a few maps of the whole Sun at the two wavelengths are now taken daily. In this presentation, we will introduce the instrument and present some observational results.

• 천문학회보
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• 제22권
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• pp.5.1-5.1
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• 1997

• Journal of Astronomy and Space Sciences
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• 제19권3호
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• pp.231-242
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• 2002

소간의는 천체의 위치를 관측하고 시간을 측정할 수 있는 천문 관측 기기로서 세종16년 (1434년)에 이천, 정초, 정인지가 제작한 천문의기 이다. 우리는 소간의의 문헌과 관측기록을 수집하여 정리하였다. 소간의는 적도좌표계와 지평좌표계를 선택하여 관측할 수 있어서 천체의 적경과 적위, 고도와 방위를 측정할 수 있다 그 구조는 사유환, 적도환, 백각환, 규형, 용주, 부(받침대)로 구성되어 있다. 소간의는 천체의 위치를 파악하는 것은 물론 주야의 시간 측정과 이동식 측량기로 활용할 수 있는 이동식 다목적 천문의기 이다.

• Journal of Astronomy and Space Sciences
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• 제34권1호
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• pp.45-54
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• 2017

This study examines the scale unique instruments used for astronomical observation during the Joseon dynasty. The Small Simplified Armillary Sphere (小簡儀, So-ganui) and the Sun-and-Stars Time-Determining Instrument (日星定時儀, Ilseong-jeongsi-ui) are minimized astronomical instruments, which can be characterized, respectively, as an observational instrument and a clock, and were influenced by the Simplified Armilla (簡儀, Jianyi) of the Yuan dynasty. These two instruments were equipped with several rings, and the rings of one were similar both in size and in scale to those of the other. Using the classic method of drawing the scale on the circumference of a ring, we analyze the scales of the Small Simplified Armillary Sphere and the Sun-and-Stars Time-Determining Instrument. Like the scale feature of the Simplified Armilla, we find that these two instruments selected the specific circumference which can be drawn by two kinds of scales. If Joseon's astronomical instruments is applied by the dual scale drawing on one circumference, we suggest that 3.14 was used as the ratio of the circumference of circle, not 3 like China, when the ring's size was calculated in that time. From the size of Hundred-interval disk of the extant Simplified Sundial in Korea, we make a conclusion that the three rings' diameter of the Sun-and-Stars Time-Determining Instrument described in the Sejiong Sillok (世宗實錄, Veritable Records of the King Sejong) refers to that of the middle circle of every ring, not the outer circle. As analyzing the degree of 28 lunar lodges (lunar mansions) in the equator written by Chiljeongsan-naepyeon (七政算內篇, the Inner Volume of Calculation of the Motions of the Seven Celestial Determinants), we also obtain the result that the scale of the Celestial-circumference-degree in the Small Simplified Armillary Sphere was made with a scale error about 0.1 du in root mean square (RMS).

• 천문학논총
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• 제28권2호
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• pp.17-23
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• 2013

Song I-Yeong (1619 ~ 1692), who was an astronomy professor of Gwansanggam (觀象監, Bureau of Astronomy), created the Honcheonsigye (渾天時計, Armillary Clock) in 1669 (10th year of King Hyeonjong Era). Honcheonsigye was a unique astronomical clock which combined an armillary sphere, the traditional astronomical instrument of the Far East, with the power mechanism of western alarm clock. The clock part of this armillary clock is composed of two major parts which are the going-train, power unit used the weight, and the time signal system in a wooden case. The time signal system is composed of four parts which are the time-annunciator, the striking train, the 12 different time-announcing medallions and the sound bell. This clock has been neglected for many years and its several components have been lost. This study is to understand the structure of time signal system and suggests the restoration process.

• 천문학논총
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• 제27권3호
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• pp.61-69
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• 2012

The Ganui (簡儀, simplified armillary sphere) is a representative of astronomical instruments in Joseon Dynasty of Korea, as well as Yuan Dynasty and Ming Dynasty of China. In early 15th century, Joseon's scientists and engineers uniquely developed the Soganui (小簡儀, small simplified armillary sphere) and the Ilseongjeongsiui (日星定時儀, sun-and-star time determining instrument) from the structural characteristic of Ganui. These two astronomical instruments had a new design by the miniaturization and felt convinced a similar performance of Ganui in the harmony with Korean Astronomy and Astrology Cultures. Since mid-18th century after the enforcement of shixian-li (時憲曆), the Soganui and Ilseongjeongsiui handed over the Jeokdogyeongwiui (赤道經緯儀, equatorial armilla) by a change of the observational framework such as the time and angle measures. The Jeokdogyeongwiui made by Gwansanggam (觀象監, Bureau of Astronomy in Joseon Dynasty) adopted the new observational framework. We studied the structural characteristics and scientific values of these 3 astronomical instruments with theirs observation methods.

• 천문학회보
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• 제46권2호
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• pp.63.1-63.1
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• 2021

We present status of solar astronomy in North Korea through analysis of research papers written by North Korea scientists. For the study, we collected 42 papers published in North Korea and international journals. We have analyzed the papers statistically according to three criteria such as research subject, research field, and research members. The main research subjects are the sunspot (28%), observation system (21%), and space environments (19%). The research fields are distributed with data analysis (50%), numerical method (29%), and instrument development (21%). There have been 25 and 9 researchers in the solar astronomy and space environment, respectively since 1995. North Korea's solar research activities were also investigated in three area: instrument, solar physics, and international research linkage. PAO(Pyongyang Astronomical Observatory) has operated two of sunspot telescope and solar horizontal telescope for spectroscopy and polarimetry, but there is no specific information on solar radio telescopes. North Korea has cooperated in solar research with Europe and China. We expect that the results of this study will be used as useful resource in supporting astronomical cooperation between South and North Korea in the future.

• 천문학회보
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• 제38권1호
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• pp.67.1-67.1
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• 2013

The CFHT currently has three instruments running in QSO mode and one in Classical mode. I will touch on the capabilities of these instruments and give an update on the future instrumentation at CFHT. One new instrument, SITELLE, is scheduled to be delivered to CFHT at the end of the year. Another instrument which is a proof of concept is GRACES which should see first light during the summer. I will also give an update on the Dome Venting project and the Next generation CFHT.

• 천문학논총
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• 제30권2호
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• pp.663-664
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• 2015

The activities of IRSF, a 1.4m infrared telescope operated under collaboration between Japan and South Africa, are presented briefly. The dedicated instrument, SIRIUS, which sits at the Cassegrain, has produced unique and prosperous science for 14 years. My talk involves; ${\circ}$ concept of construction and operation, ${\circ}$ publications and education, ${\circ}$ the successive upgrading of the instrument, and ${\circ}$ future plans.