• The Bulletin of The Korean Astronomical Society
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• v.40 no.1
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• pp.57.3-57.3
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• 2015

We present a test observation result of the KMTNet Intensive Nearby Southern Galaxy group Survey (KINGS). The KINGS is designed to study nearby galaxy groups (NGC 55, NGC 253, NGC 5128, and M83 groups), taking the advantage of the wide field coverage of the KMTNet. The main goal of the KINGS is to produce extensive catalogs of dwarf galaxies, ultra compact dwarfs (UCDs), and intraglobular clusters in the galaxy groups. We will also investigate the spatial distribution of intragroup light in each group. We present a progress report of the project based on the test BVI observations of two galaxy groups. We discuss the result from the test observation and possible improvement for future observations.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.11
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• pp.150-158
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• 1996

Physiological observations reported and the perceptual phenomena that some simple arrays of discrete dots are perceived as a continuous curve, and others are perceived as an angular contour or as consisting of separate goups of dots. The perception of continuous curves versus discondinuous angles is mainly determined by the relative orientations of the dots, i.e., by the angles between sucessive virtual lines, whereas the length of the virtual lines gives little influence. It is important that the perception of dot stimuli is presented by vitual lines between dots in visual information processing. In this paper, on the basis of these facts of physiological observations, some experimental results on the perception of visual lines form dot stimuli are shown. Triples of the dots used in the experiment are similar to those of smith & Vos' physiological experiments.

• Journal of Astronomy and Space Sciences
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• v.32 no.4
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• pp.341-348
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• 2015

New observations for the times of minimum lights of a well-known apsidal motion star CW Cephei were made using a 0.6 m wide field telescope at Jincheon station of Chungbuk National University Observatory, Korea during the 2015 observational season. We determined new times of minimum lights from these observations and analyzed O-C diagrams together with collected times of minima to study both the apsidal motion and the Light Time Effect (LTE) suggested in the system. The new periods of the apsidal motion and the LTE were calculated as 46.6 and 39.3 years, respectively, which were similar but improved accuracy than earlier ones investigated by Han et al. (2002), Erdem et al. (2004) and Wolf et al. (2006).

• Journal of The Korean Astronomical Society
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• v.37 no.5
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• pp.337-342
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• 2004

The presence of magnetic fields in the intracluster medium in clusters of galaxies has been revealed through several different observational techniques. These fields may be dynamically important in clusters as they will provide additional pressure support to the intracluster medium as well as inhibit transport mechanisms such as thermal conduction. Here, we review the current observational state of Faraday rotation measure studies of the cluster fields. The fields are generally found to be a few to 10 $\mu$G in non-cooling core clusters and ordered on scales of 10 - 20 kpc. Studies of sources at large impact parameters show that the magnetic fields extend from cluster cores to radii of at least 500 kpc. In central regions of cooling core systems the field strengths are often somewhat higher (10 - 40 $\mu$G) and appear to be ordered on smaller scales of a few to 10 kpc. We also review some of the recent work on interpreting Faraday rotation measure observations through theory and numerical simulations. These techniques allow us to build up a much more detailed view of the strength and topology of the fields.

• Bulletin of the Korean Space Science Society
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• 1995.04a
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• pp.21-21
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• 1995

The structures of 17GHz microwave burst for bipolar sunspots have investigated. which included the effects of the projected shapes of radio sources as they traverse across the solar disk using a magnetic loop employing a model of solenoid coils. An ensemble of high-energy electrons confined in the loop be assumed. The projected brightnesls distributions of gyrosynchrotron emission in x- and o-modes are computed and converted into total intensity and circular polarization difference at 17GHz for various heliocentric distances using numerical integration of the transfer equation along the line of sight. The results of computations at 17GHz for optical thin case will be presented. and the effects of the orientation of the loop will be discussed in detail, as well as the effect of size, position, Structure, and polarization of the emission. Also the results of the various physical P8lrameters such as the strength of magnetic field. high and low energy cut-off of accelerated electrons. spectral index and density of electrons will be preslmted. After comparing the results of model calculation with observations. we found that the observations can be well explained in terms of a loop model and its projection effect.effect.

• Proceedings of the KSRS Conference
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• 2004.10a
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• pp.386-388
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• 2004

The International Space Station (ISS) offers research opportunities to researchers through crew's space mission in the field of remote sensing. ISS provides the facilities to place and operate experiment equipments in a variety of fields, especially, microgravity experiments and Earth observations. This paper is intended to give readers a brief introduction to the ISS utilization and the capabilities for remote sensing researches. We investigate what kind of crew missions and payloads should be developed for remote sensing researches on the ISS.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.2
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• pp.83.2-83.2
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• 2017

We report observations of light bridge (LB) jets taken with the New Solar Telescope. Jets as dark, fine threads occurred lined along both edges of a LB of a sunspot, which is a bright and elongated structure that divides a sunspot's umbra into two or more parts. This LB jets are observed for about three hours with $H{\alpha}$ filtergraph at ${\pm}0.4{\AA}$, ${\pm}0.8{\AA}$ from the line center, TiO filtergraph, and near infra-red imaging spectropolarimeter (NIRIS). High resolution $H{\alpha}$ data revealed that subsequent ejection of LB jets were associated with subsequent brightening along the edge of the LB. Also, this subsequent brightening was spatially correlated with both photospheric flow and magnetic field change detected from the TiO and NIRIS data, respectively. Preliminary results of LB jet observation and discussions on its formation mechanism will be presented.

• Publications of The Korean Astronomical Society
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• v.20 no.1 s.24
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• pp.29-35
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• 2005

Time-series observations were carried out using a 155mm refractor and a $2k{\times}3k$ CCD camera at Bohyunsan Optical Astronomy Observatory. We found 38 new variable stars in the $2.3^{\circ}{\times}2.4^{\circ}$ region around the Cepheid variable TU Cas: 22 eclipsing binary stars, 11 ${\delta}$ Scuti type stars and an RR Lyrae star, and 4 unclassified variables.

• The Bulletin of The Korean Astronomical Society
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• v.35 no.1
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• pp.28.1-28.1
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• 2010

Ground-based solar observations have several merits such as wider field of view and higher time cadence than those of satellite observations. The Domeless Solar Telescope of Hida Observatory is designed to acquire solar surface images at the highest possible spatial resolution using two types of spectrographs: a vertical spectrograph with the highest wavelength resolution in the world, and a horizontal spectrograph that can take images of the sun in multi-wavelength over the entire visible solar spectrum. The temporal variation of fine features such as chromospheric grains in the supergranulation cells and facular points in the network region has been obtained using DST Ca II K lines compared with Hinode Ca II H lines. This analysis is expected to provide a fundamental tool for research of diverse phenomena on the solar surface.

• International Journal of Industrial Entomology and Biomaterials
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• v.5 no.1
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• pp.127-129
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• 2002

Lepidoscelio viatrix is a potential biocontrol agent of the eggs of wingless grasshopper, Neorthacris acuticeps nilgerensis, in mulberry plantation in natural conditions. The present investigation was undertaken to understand the attachment of the parasite to the hopper under scanning electron microscope and the oviposition behavior of the parasite. The results reveal that the parasite grips firmly to the lateral and dorsal surfaces of the female grasshopper with its mandibles implanted in the intersegmental membranes of the abdominal segments. During oviposition, L. viatrix initially turn around the egg pod and protrude its ovipositor and insert into the eggs. It lays eggs inside the eggs of grasshopper by an up and down movement of the ovipositor, Further, field observations indicated a drastic fall in the incidence of the grasshopper population on mulberry, with the increased parasitization of L. viatrix.