• Publications of The Korean Astronomical Society
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• v.18 no.1
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• pp.37-41
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• 2003

We have developed a seeing monitoring system and measured seeing variation of the Bohyunsan Optical Astronomy Observatory (BOAO) and the Sobaeksan Optical Astronomy Observatory (SOAO) using a small telescope system. Our seeing monitoring system is similar to the differential image motion monitor (DIMM) installed at the ESO. The ooly difference between the BOAO and the SOAO seeing monitoring system is a detector system, a video camera at the BOAO and ST-4 camera at the SOAO. We confirmed that the seeing monitoring system at the SOAO can measure average seeing size inspite of its simple detector system. From the BOAO seeing measurement, we found that the seeing size changes fast. We expect that our seeing monitoring system could be used for real time seeing monitoring after some improvement, and the data to be obtained would be very useful when we build adaptive optic system in the future.

• Journal of the Korean earth science society
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• v.30 no.4
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• pp.485-494
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• 2009

We report patterns of astronomical seeing at KSA SEMO (Korea Science Academy Space Earth and Man Observatory). Though the data of the seeing measured at the local observatory is essential in identifying the seeing of the observatory, systematic measurement of seeing has not been made in Pusan yet. For this reason, KSA SEMO adopted the Santa Barbara Instrument Group (SBIG) Seeing Monitor to constantly record the seeing. The seeing monitoring was done through an elaborate procedure involving direct CCD images in the focal plane which were subsequently analyzed for the full width at half maximum (FWHM) Gaussian widths. Based on the seeing monitoring for 8 months, we classified five patterns of the seeing at KSA SEMO: 'Sunset/Sunrise Effect', 'Extreme Fluctuation', 'Sudden Increment', 'Daily Variation' and 'Stable Condition'. Seeing was generally good from 1:00 am to 3:00 am than other times, and it was also better in Winter than in Summer.

• Journal of The Korean Astronomical Society
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• v.45 no.1
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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.

• Publications of The Korean Astronomical Society
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• v.11 no.1
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• pp.177-196
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• 1996

We have investigated the astronomical observational environments at the Choejung-san GEODSS site which is located at the south of Taegu, Korea. As a part of the investigation, seeing and night sky brightness were measured outside nearby the GEODSS site using the Celestron 8-inch portable reflector with $192{\times}165$ pixels Lynxx CCD camera during the period of December 1994 to April 1996. The average seeing values of 4.8 arcsecond in B filter and 5.1 arcsecond in V filter were determined using the IRAF software. These values might be overestimated and would be reduced by at least 1 arc second in both filters if they were measured by more stable telescope system with solid mount and under a dome. We also compare the average seeing value at the GEODSS site with those at three other observatories, the Bohyunsan Optical Astronomy Observatory, the Sobaeksan Optical Astronomy Observatory, and the Seoul National University Observatory, for justification of the above guess. Unfortunately the night sky brightness measurement was not successful mainly due to the short exposure time. The utilizing plan of the GEOSS site is discussed based on the average seeing value, naked-eye sky brightness measurement, analysis of the existing thirty-year weather data and twenty-year urban planning of the metropolitan Taegu city for the year of 2016.

• The Bulletin of The Korean Astronomical Society
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• v.34 no.1
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• pp.188.1-188.1
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• 2009

• The Bulletin of The Korean Astronomical Society
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• v.40 no.2
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• pp.59.2-59.2
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• 2015

국립고흥청소년우주체험센터는 2014년부터 덕흥천문대에 설치된 SBIG사의 "Seeing Monitor"로 시상을 측정하고 있다. "Seeing Monitor"는 북극성을 대상으로 TDI(Time Delay and Integration) 방식을 적용하여 얻어진 시상을 분 단위로 저장해준다. 따라서 구름이 없는 맑은 날의 분 단위 시상 자료와 주변 환경 정보를 조합하여 시상에 영향을 미치는지 환경 요인을 정량적으로 분석하는 것이 가능하다. 그 첫 단계로 측정된 시상 자료와 기상청의 온도 습도 풍속 자료, 그리고 GFS(Global Forecast System)의 고도별 상층 풍속 자료를 비교하여 기상정보와 시상과의 관계를 분석해보았다. 습도와 바람이 시상에 가장 큰 영향을 주었으며, 지상 풍속 1~2m/s, 습도 75% 이하, 제트기류 풍속은 250km/h 이하 일 때 좋은 시상 값을 얻을 수 있었다. 이를 통해 덕흥천문대에서 기상정보를 통해 시상이 안정적인 날을 예측할 수 있다면, 앞으로 도입될 1m 망원경으로 훌륭한 관측 자료를 얻을 수 있을 것이라 기대된다.

• The Bulletin of The Korean Astronomical Society
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• v.20
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• pp.23.1-23.1
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• 1995

• The Bulletin of The Korean Astronomical Society
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• v.21
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• pp.11.1-11.1
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• 1996

• Publications of The Korean Astronomical Society
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• v.19 no.1
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• pp.55-63
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• 2004

Observation environment of the Bohyunsan Optical Astronomy Observatory(BOAO) has been examined using various statistical data including real observation times versus allocated times and seeing statistics. The data have been collected from the observation logs of the 1.8m telescope in the period 1998 - 2004. New criteria have been set up to calculate a more realistic observation efficiency of the observatory. The new statistical analysis based on the new criteria gives the overall observation efficiency of BOAO as $38.6\%$, that is equivalent to 115.8 observable nights out of 300 allocatable nights. The seeing statistics shows that the mean seeing measured at the focal images is 2".3. The present study of the observation environment of BOAO suggests that differential photometry and spectroscopy should be preferred modes of observation to maximize the productivity of BOAO.

• The Bulletin of The Korean Astronomical Society
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• v.43 no.2
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• pp.44.1-44.1
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• 2018

Since its installation on March 27th, 2018, the SAO 1-m telescope has been operating for about 5 months. We report first results of these observations in this presentation. Sample images were taken with a $4096{\times}4096$ CCD camera (Field of view of ${\sim}21{\times}21arcmin^2$) and their characteristics such as seeing value, and limiting magnitudes are presented. The best seeing value is 0.85 arcsecond on July $16^{th}$, 2018. We find that the 5 sigma detection limit is about 20 magnitude AB in B, V, R, I bands with about 10-20 min exposures. We will also briefly introduce the spectrum of a faint transient taken with the spectrograph also installed on the SAO 1-m telescope.