• 천문학회보
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• 제35권2호
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• pp.61.2-61.2
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• 2010

CQUEAN (Camera for Quasars in EArly uNiverse) is an optical CCD camera system which has its own auto-guiding system. Guiding system consists of a 1k*1k CCD camera, FLI PL1001E, a flat mirror to feed the image of an off-axis field to the camera and baffle. The whole system lies on a moving arm which rotates 90 degree effectively to enlarge the field of view. A motor, IMS MDRIVE 34, and a differential decelerator, APEX AD140-050, are used for the moving mechanism. Auto-guiding is controlled by Agdr program. We had a first light from Aug. 10 to Aug 17, 2010 at McDonald Observatory, USA. In this presentation, we describe about the auto-guiding system for CQUEAN and its performance on the 2.1m telescope.

• 천문학회보
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• 제42권1호
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• pp.57.2-57.2
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• 2017

Remote and robotic telescopes are the most effective instrument for astronomical survey projects. The system is based on the dynamic operation of all astronomical instruments such as dome and telescope control system (TCS), focuser, filter wheel and data taking camera. We adopt the ASCOM driver platform to control the instruments through the integrated software. It can convert different interface libraries from various manufacturers into a uniform standard library. This allows us to effectively control astronomical instruments without modifying codes. We suggest a conceptual design of software for automation of a small telescope such as the new wide-field 0.25m telescope at McDonald Observatory. It can also be applied to operation of multi-telescopes in future projects.

• 천문학회보
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• 제36권2호
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• pp.55.2-55.2
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• 2011

We present the current research activities of the Center for the Exploration of the Origin of the Universe, a center established at Seoul National University with the Creative Research Initiative program. Our activities focus on observational studies of distant objects such as gamma-ray bursts, quasars, and proto-cluster of galaxies, but we also carry out other observational and theoretical studies in related topics. We also developed a new instrument, Camera for Quasars at Early Universe (CQUEAN) in collaboration with Kyunghee University group, and have secured observing facilities such as UKIRT and McDonald 2.1m observatory. Our research highlights include results such as the discovery of high redshift quasars and gamma ray bursts, the discovery of tidal disruption event at z=0.38 and peculiar gamma ray burst events, analysis of proto-clusters of galaxies, the discovery of brown dwarfs, and development of CQUEAN and its usage at the McDonald observatory.

• 아태비즈니스연구
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• 제10권4호
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• pp.181-195
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• 2019

This study aims to investigate the influencing attributes on price fairness in the domain of fast food service context. As the research subject, this research selects McDonald's business because of its market share in the fast food market. Five attributes are examined to account for price fairness. The attributes are advertising attitude, employee service, waiting, convenience, and brand love. This study performed survey to collect the data. The survey participants are university students because they are essential market segment for fast food business. The number of observation is 299 for the data analysis. To analyze the data, this research used various statistical instruments (e.g., frequency analysis, mean and standard computation, exploratory factor analysis, reliability test, correlation matrix, and multiple regression analysis). Regarding the results, this research identified advertising attitude, employee service, and brand love are influential attributes to establish price fairness of university students. This research could inform the marketing director of food service business to understand university students target better.

• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2006년도 제33회 추계학술대회 발표논문집
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• pp.20-22
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• 2006

• 대한자원환경지질학회:학술대회논문집
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• 대한자원환경지질학회 2002년도 춘계 공동학술발표회
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• pp.11-13
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• 2002

• 천문학회보
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• 제19권
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• pp.6.1-6.1
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• 1994

• 천문학회보
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• 제35권1호
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• pp.38.1-38.1
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• 2010

McDonald 2.1m Otto Struve Telescope is located in the Davis Mountains, 450 miles west of Austin, Texas. The telescope was built in 1938, but it is still in demand today. CQUEAN (Camera for QUasar in Early uNiverse) will be attached on this telescope and perform Y-band imaging observations. Dynamics study of the telescope shows that tracking errors are 0.1 arcsec/100sec in declination direction and 0.4 arcsec/100sec in R.A. direction. In order to allow a long exposure (> a few minutes) of a target field, we are making auto-guiding system for the 2.1m telescope. The auto-guiding system of CQUEAN will be connected with TCS of the telescope. The expected number of stars on the CCD field (2.97 square arcminutes) is about 1.2 stars which are brighter than magnitude 17.5 in 2.97 square arcminutes. For more effective observation, we plan to implement moving mechanism in guiding system so that guide CCD camera can see wider off-axis fields.

• 천문학회보
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• 제35권1호
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• pp.36.2-36.2
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• 2010

The CQUEAN (Camera for QUasars in EArly uNiverse) is an optical CCD camera optimized for observation of high redshift objects. It is going to be attached to the cassegrain focus of 2.1m telescope at McDonald Observatory, USA. We are making a focal reducer for CQUEAN to secure a larger field of view. The focal reducer is composed of four spherical lens, and it reduces the focal length of telescope by one third. We designed the lens configuration, performed tolerance analysis, and estimated the optical performance with ZEMAX. The differences in optical performace with/without filters were also investigated. The result from ZEMAX shows that the system has ample margin of errors for median seeing of 1.2" at McDonald observatory. Even with aberration and alignment tolerance, the performance is better than the original requirement. The lenses are now being made, and the lens barrel and an adapter for assembly of the Andor CCD camera and the filter wheel is now under designing process. We expect that the manufacturing of the focal reducer system as well as its optical test will be finished by April 2010.

• 천문학회보
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• 제42권1호
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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.