• Publications of The Korean Astronomical Society
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• v.27 no.4
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• pp.375-380
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• 2012

The Herschel Space Observatory is the European Space Agency's state of the art infrared space telescope launched into space on 14 May 2009, covering the wavelength range from 70-700 microns with 3 instruments SPIRE, PACS and HIFI. Large area surveys are being carried out by Herschel in the AKARI legacy fields at the North and South Ecliptic Poles and the AKARI All-Sky Survey provides additional synergy with the largest survey with Herschel, H-ATLAS, covering more than 500 square degrees. This paper reports on some of the early results of these synergies between Herschel and AKARI including the first comparison of the AKARI All-Sky Survey number counts with the deeper Herschel surveys.

• The Bulletin of The Korean Astronomical Society
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• v.32 no.2
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• pp.63.1-63.1
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• 2007

• Bulletin of the Korean Space Science Society
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• 2005.04a
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• pp.38-38
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• 2005

• Bulletin of the Korean Space Science Society
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• 2008.10a
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• pp.32.4-33
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• 2008

Korea space weather prediction center (KSWPC) in Korea Astronomy and Space Science Institute (KASI) has been constructing several facilities to observe mid- to low-latitude upper atmospheric/ionospheric phenomena; VHF coherent scattering radar, All-sky Imager, and Scintmon. Those new ionospheric facilities can be integrated to produce more reliable space weather forecast and nowcast with the existing facilities; Solar Flare Telescope (SOFT), Solar Optical Observatory's sunspot telescope and solar imaging spectrograph, and Magnetometer. The specification of KASI VHF coherent scattering radar is 40.8 MHz of target frequency, 200 kHz of bandwidth, 24 kW of peak power. The science goal of this radar is to measure the irregularities in E- and F-layers over Korea, especially sporadic-E, spread-F, and traveling ionospheric disturbance (TID). The radar will be installed at Gyerong in a territory of Korean Air force by early 2009.

• The Bulletin of The Korean Astronomical Society
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• v.35 no.2
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• pp.57.1-57.1
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• 2010

The SPICA (SPace Infrared Telescope for Cosmology & Astrophysics) is a next generation infrared space telescope being prepared by JAXA, ESA and other international collaborators. We propose to develop FPC (Focal Plane Camera) consisting of two near-infrared cameras: FPC-G (I band) for focal plane guidance and FPC-S (0.7 - 5 um) for a back-up of FPC-G and a NIR instrument for scientific observations. In this talk, we introduce the requirement and the design concept of the FPC as well as the development strategy of the project.

• The Bulletin of The Korean Astronomical Society
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• v.35 no.2
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• pp.56.2-56.2
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• 2010

The SPICA (SPace Infrared Telescope for Cosmology & Astrophysics) project is a next-generation astronomical mission optimized for mid- and far-infrared observation with a cryogenically cooled 3m-class telescope. Due to its high angular resolution and unprecedented sensitivity, SPICA will enable us to resolve many key issues in the present-day astronomy. As an international collaboration, KASI proposed the near-infrared instrument which is composed of two parts; (1) science observation with the capability of imaging and spectroscopy covering $0.7{\mu}m$ to $5{\mu}m$ (FPC-S) (2) fine guiding to stabilize and improve the attitude (FPC-G). Here, we introduce the science programs proposed for SPICA/FPC-S.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.1
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• pp.61.2-61.2
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• 2019

A total of 10,317 hours of the KMTNet telescope time were allocated for the predefined science programs, and 7,765 hours have been used for science exposures in Chile, Australia and South Africa last year. The success rate of science observation has increased from 70.7% to 75.3%, and the system operation rate has also increased from 97.6% to 99.6%. There were many improvements in mechanical parts of the dome structure and telescope system, and newly installed filter driers of the CCD camera increased the stability of the system by preventing contamination of oil in the gas line in advance. In order to prepare for the time domain astronomy and multi messenger astronomy era, a pilot program was designed and is now being tested. It targets for fast follow-up observations of optical transient events, however it runs during twilight times only so it does not interrupt any granted science program. A total of 32 SCI papers were published using the system in 2018 and it is a good indication of the high science performance of KMTNet. The selection process of the next observation programs starting from October 2020 and its timeline will be discussed in this meeting.

• The Bulletin of The Korean Astronomical Society
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• v.38 no.1
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• pp.72.1-72.1
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• 2013

Camera for QUasars in EArly uNiverse (CQUEAN) is an optical CCD camera, developed by Center for Exploration of Origin of the Universe (CEOU), which is now searching for high red shift quasar candidates. It has been operated since 2010, attached to the 2.1m Otto Struve telescope at the McDonald Observatory, USA. Based on the previous operation experiences, we present CQUEAN II system design which has a new filter wheel allowing with 20 narrow band filters. In addition, the auto guiding system will be rearranged and the interfacing units between the telescope and the instrument will become stabilized.

• Bulletin of the Korean Space Science Society
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• 2010.04a
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• pp.34.3-34.3
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• 2010

We present the results of flux monitoring of BL Lac object 0716+71 and 0954+65 at 22GHz and 43GHz. Both of the flat spectrum radio sources are known as Intraday variables (IDVs) which are characterized by fast flux variation on time scales of a day or less. In general, the IDV phenomenon is interpreted as the effect of refractive scintillation in the interstellar medium or the evidence of source intrinsic flux variation. The observations were made simultaneously at 22GHz and 43GHz with KVN Yonsei 21m radio telescope.

• Journal of The Korean Astronomical Society
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• v.54 no.4
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• pp.113-119
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• 2021

It is difficult for observers to conduct an optical alignment at an observatory without the assistance of an optical engineer if optomechanical parts are to be replaced at night. We present a practical tilt correction method to obtain the optimal optical alignment condition using the symmetricity of optical aberrations of a wide-field on-axis telescope at night. We conducted coarse tilt correction by visually examining the symmetry of two representative star shapes obtained at two guide chips facing each other, such as east-west or north-south pairs. After coarse correction, we observed four sets of small stamp images using four guide cameras located at each cardinal position by changing the focus positions in 10-㎛ increments and passing through the optimum focus position in the range of ±200 ㎛. The standard deviation of each image, as a function of the focus position, was fitted with a second-order polynomial function to derive the optimal focus position at each cardinal edge. We derived the tilt angles from the slopes converted by the distance and the focus position difference between two paired guide chip combinations such as east-west and north-south. We used this method to collimate the on-axis wide-field telescope KMTNet in Chile after replacing two old focus actuators. The total optical alignment time was less than 30 min. Our method is practical and straightforward for maintaining the optical performance of wide-field telescopes such as KMTNet.