• Journal of The Korean Astronomical Society
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• v.36 no.spc1
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• pp.145-149
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• 2003

LIST is the Lyman-$\alpha$ Imaging Solar Telescope, a project funded by the Korean government to fly on the second Korean Science and Technology research Satellite (STSat-2) due to launch in December 2005. The Principal Investigator is Dr. Minhwan Jang of Kyung-Hee University and of the Space Payload Research Center (SPARC), a consortium of Korean universities and institutions formed to develop scientific research projects in space. The purpose of the LIST project is to design, build, and operate an instrument on STSat-2 which will make images of the Sun from Earth orbit at the wavelength of the Hydrogen Lyman-a emission line at 121.6 nm. LIST has a simple design concept comprised of a small telescope to image the full disk of the Sun onto a CCD detector and a set of filters to isolate the 121.6 nm wavelength.

• Journal of Astronomy and Space Sciences
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• v.19 no.3
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• pp.173-180
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• 2002

Images taken with the Chandra X-ray telescope have for the the first time revealed the central, wind-driven, hot bubble (Chu et al. 2001), while Hubble Space Telescope (HST) WFPC2 images of the Cat's Eye nebula, NGC 6543, show that the temperature of the halo region of angular radius ~ 20", is much higher than that of the inner bright H II region. With the coupling of a photoionization calculation to a hydrodynamic simulation, we predict the observed 〔O III〕 line intensities of the halo region with the same O abundance as in the core H II region: oxygen abundance gradient does not appear to exist in the NGC 6543 inner halo. An interaction between a (leaky) fast stellar wind and halo gas may cause the higher excitation temperatures in the halo region and the inner hot bubble region observed with the Chandra X-ray telescope.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.1
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• pp.63.3-63.3
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• 2016

NYSC 1m telescope is completely assembled now, and equipped with FLI PL-16803 4k CCD and Shelyak eShel spectrograph (R~10,000) on optical system of f/8. From 12th Jan 2016, optical system alignment and test observations have been performed. We present the result of M35 photometric observation for the performance test of the 1m telescope. The photometric observation was carried out for the central part of M35 with the field of view, ${\sim}15^{\prime}.8{\times}15^{\prime}.8$. Standard transformation to the UBVI system was done by the photometric data of M35 in Sung and Bessell(1999).

• Publications of The Korean Astronomical Society
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• v.30 no.2
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• pp.655-657
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• 2015

The Australia Telescope National Facility (ATNF) consists of the Parkes and Mopra radio telescopes, and the Australia Telescope Compact Array, with the first elements of the wide-field Australian Square Kilometer Array Pathfinder (ASKAP), currently being commissioned. The capabilities of these facilities are described.

• The Bulletin of The Korean Astronomical Society
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• v.35 no.1
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• pp.39.1-39.1
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• 2010

We are developing a CCD camera named CQUEAN (Camera for Quasars in Early Universe) to search for quasars at z > 7. CQUEAN has a 1024*1024 deep depletion CCD chip and will be attached to 2.1m Otto-Struve Telescope at McDonald Observatory, USA. Although commercial software for the CCD camera is provided by the vendor, we are going to develop our own software to control the other instruments as well, to carry out efficient observation. There are four major parts in our software: Instrument control part controls the camera and filter wheel to obtain imaging data. Quick look window is to display acquired imaging data for quick inspection. Telescope control part interfaces with Telescope Control System (TCS) to move the telescope and to get time or coordinate information. Finally, Observation scripting facility part carries out a series of short exposures in a batch. The whole software will be written in python on linux platform, using the instrument control software libraries provided by the vendors.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.210.1-210.1
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• 2012

We report technique used for improved measurement uncertainties for Photon detection efficiency(PDE) of $1mm^2$ single pixel SiPM. It consists of 470nm LED light source, two 2-inch integrating sphere and two NIST calibrated silicon photodiodes that have ${\pm}2.4%$ calibration error. With raytracing simulation of our experimental setup, we predict number of photon into SiPM and measurement uncertainty. For MPPC, Hamamatsu suggested PDE(1600 micro pixel) including crosstalk and afterpulse is 23.5% at 470 nm. By using new low calibration error photodiode and raytracing simulation, our simulation result has ${\pm}3%$ measurement uncertainty. The technical detail of measurement, simulation are presented with the results and implication.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.1
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• pp.34.2-34.2
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• 2017

A small wide-field imaging telescope is a powerful instrument to survey the Universe: wide-field image can monitor the variability of many sources at a time, e.g. young stellar objects and active galactic nuclei, and it can be an effective way to locate transient sources without precise positional information such as gravitational wave sources or some gamma-ray bursts. In February 2017, we installed a 0.25 m f/3.6 telescope on the McDonald 0.8 m telescope as a piggyback system. With a $4k{\times}4k$ CCD camera, the telescope has a $2.35{\times}2.35deg$ field-of-view. Currently, it is equipped with Johnson UBVRI filters and 3 narrow-band filters: $H{\alpha}$, OIII and SII. We will present the installation process, and the telescope performance such as detection limit and image quality based on the data from commissioning observations. We will also discuss possible scientific projects with this system.

• Journal of Astronomy and Space Sciences
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• v.21 no.2
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• pp.121-128
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• 2004

As the first step of the real time monitoring system of the solar radio disturbance, we constructed the control system of the solar radio telescope. An 1.8m antenna built by Korean Astronomy Observatory has been used, and the observed radio flux is transformed to the digital signal by the powermeter. We have also developed a computer program CBNUART in order to control the telescope system and the powermeter. As the sun rises, the telescope begins to observe the sun, and ends the observation automatically at sunset. The CBNUART enables the telescope automatically to go to the position of the sunrise for the beginning the observation and come back to the setposition after the ending the observation at the sunset. An active tracking routine is adopted in order to improve the tracking accuracy of the control system, and we used an optical telescope equipped in front of the antenna for control test. The tracking test shows that our control system can track with the accuracy of arc seconds, and the 50 minute pointing test shows that the pointing accuracy of right ascension and declination are 1.12 and 0.08 arc minutes respectively.

• Journal of The Korean Astronomical Society
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• v.38 no.2
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• pp.187-190
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• 2005

The Cosmic Evolution Survey (COSMOS) is a Hubble Space Telescope (HST) treasury project. The COSMOS aims to perform a 2 square degree imaging survey of an equatorial field in I(F814W) band, using the Advanced Camera for Surveys (ACS). Such a wide field survey, combined with ground-based photometric and spectroscopic data, is essential to understand the interplay between large scale structure, evolution and formation of galaxies and dark matter. In 2004, we have obtained high-quality, broad band images of the COSMOS field (B, V, r', i', and z') using Suprime-Cam on the Subaru Telescope, and we have started our new optical multi-band program, COSMOS-21 in 2005. Here, we present a brief summary of the current status of the COSMOS project together with contributions from the Subaru Telescope. Our future Subaru program, COSMOS-21, is also discussed briefly.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.10a
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• pp.132-136
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• 2003

A Multi-Spectral Camera (MSC) is the payload of KOMPSAT-2 which is designed for earth imaging in visible and near-Infrared region on a sun-synchronous orbit. The telescope in the MSC is a Ritchey-Chretien type with large aperture. The telescope structure should be well stabilized and the optical alignment should be kept steady so that best images can be achieved. However, the MSC is exposed to adverse thermal environment on the orbit which can give impacts on optical performance. Metering structure which is exposed to adverse space environment should have tight requirement of low thermal expansion and hygroscopic stability. In order to meet those stability requirements in addition to fundamental structural ones telescope structure was designed with newly developed graphite-cyanate composite which has high tensile modulus, high thermal conductivity and low moisture absorption compared with conventional graphite-epoxy composite. In this paper, space-borne telescope structure with new composite material will be presented and fulfillment of stability requirements will be verified with designed structure.