Hong-Suh Yim
A5016431570- Astro and Planetary Science
- Astronomical Observations and Instrumentation
- Stellar, planetary, and galactic studies
- Space Satellite Systems and Control
- Planetary Science and Exploration
- Inertial Sensor and Navigation
- Astronomy and Astrophysical Research
- Spacecraft Design and Technology
- Gamma-ray bursts and supernovae
- Adaptive optics and wavefront sensing
- GNSS positioning and interference
- Advanced Optical Sensing Technologies
- Geophysics and Gravity Measurements
- Astrophysics and Cosmic Phenomena
- Isotope Analysis in Ecology
- Space exploration and regulation
- Satellite Image Processing and Photogrammetry
- Radio Astronomy Observations and Technology
- Atmospheric Ozone and Climate
- Solar and Space Plasma Dynamics
- Optical Systems and Laser Technology
- Image and Object Detection Techniques
- Remote Sensing and LiDAR Applications
- Distributed and Parallel Computing Systems
- Internet of Things and Social Network Interactions
Korea Astronomy and Space Science Institute
2012-2024
Space Science Institute
2015
Chungbuk National University
2012-2013
St Petersburg University
2007
Columbia University
2005
Yonsei University
1996-1997
Context.We present the observational results of multi-colour optical monitoring eight red blazars from 2003 September to 2004 February.Aims.The aim our is investigate spectral variability as well flux variations at short and long time scales.Methods.The observations were carried out using 1.0 m robotic telescope Mt. Lemmon Optical Astronomy Observatory, in Arizona, USA, 0.6 Sobaeksan Observatory 1.8 Bohyunsan Republic Korea.Results.During observations, all sources show strong with amplitudes...
The quasar 3C 279 was the target of an extensive multiwavelength monitoring campaign from 2006 January through April. An optical-IR-radio by Whole Earth Blazar Telescope (WEBT) collaboration organized around target-of-opportunity X-ray and soft γ-ray observations with Chandra INTEGRAL in mid-January, additional coverage RXTE Swift XRT. In this paper we focus on results WEBT campaign. source exhibited substantial variability optical flux spectral shape, a characteristic timescale few days....
The BL Lac object 3C 66A was the target of an extensive multiwavelength monitoring campaign from July 2003 through April 2004, involving observations throughout electromagnetic spectrum. Radio, infrared, and optical were carried out by WEBT-ENIGMA collaboration. At higher energies, observed in X-rays (RXTE), at very-high-energy (VHE) gamma-rays (STACEE, VERITAS). In addition, source has been with VLBA 9 epochs period September - December including 3 contemporaneous core campaign.The WEBT...
Abstract We describe results of a planetary defense exercise conducted during the close approach to Earth by near-Earth asteroid (99942) Apophis 2020 December–2021 March. The community has been conducting observational campaigns since 2017 test operational readiness global capabilities. These community-led exercises were carried out with support NASA’s Planetary Defense Coordination Office and International Asteroid Warning Network. campaign is third in our series exercises. goal this was...
Abstract On 2020 April 29, the near-Earth object (52768) 1998 OR2 experienced a close approach to Earth at distance of 16.4 lunar distances (LD). is potentially hazardous asteroid absolute magnitude H = 16.04 that can currently come as 3.4 LD. We report here observations this in polarimetry, photometry, and radar. Our show physical characteristics are similar those both M- S-type asteroids. Arecibo’s radar provide high albedo <?CDATA ${\hat{\sigma }}_{\mathrm{OC}}\,=$?> <mml:math...
The near-Earth asteroid 3200 Phaethon (1983 TB) is an attractive object not only from a scientific viewpoint but also because of JAXA's DESTINY+ target. rotational lightcurve and spin properties were investigated based on the data obtained in ground-based observation campaign Phaethon. We aim to refine lightcurves shape model using all available datasets via optical observation, as well our time-series 2017 apparition. Using eight 1-2-m telescopes imager, we acquired derived parameters...
Abstract As part of the International Asteroid Warning Network's observational exercises, we conducted a campaign to observe near-Earth asteroid 2019 XS around its close approach Earth on 2021 November 9. The goal was characterize errors in observation times reported Minor Planet Center, which become an increasingly important consideration as astrometric accuracy improves and more fast-moving asteroids are observed. exercise, total 957 observations during encounter were subsequently analyzed...
The detector subsystem of the Optical Wide-field Patrol (OWL) network efficiently acquires position and time information moving objects such as artificial satellites through its chopper system, which consists 4 blades in front CCD camera. Using this it is possible to get more data with same exposure by changing streaks into many pieces fast rotating during sidereal tracking. At time, from can be acquired tagger connected photo diode. To analyze orbits targets detected image a sequential...
An Optical Wide-field patroL-Network (OWL-Net) has been developed for maintaining Korean low Earth orbit (LEO) satellites' orbital ephemeris. The OWL-Net consists of five optical tracking stations. Brightness signals reflected sunlight the targets were detected by a charged coupled device (CCD). A chopper system was adopted fast astrometric data sampling, maximum 50 Hz, within short observation time. accuracy validated with precise ephemeris such as Consolidated Prediction File (CPF) and...
By using the Optical Wide-field Patrol (OWL) network developed by Korea Astronomy and Space Science Institute (KASI) we generated right ascension declination angle data from optical observation of Low Earth Orbit (LEO) satellites. We performed an analysis to verify optimum number observations needed per arc for successful estimation orbit. The currently functioning OWL observatories are located in Daejeon (South Korea), Songino (Mongolia), Oukaïmeden (Morocco). Observatory is as a test bed....
Context. The close approach of the near-Earth asteroid (99942) Apophis to Earth in 2029 will provide a unique opportunity examine how physical properties could be changed due Earth's gravitational perturbation. As result, Republic Korea is planning rendezvous mission Apophis. Aims. Our aim was use photometric data from apparitions 2020-2021 refine shape model and spin state Methods. Using thirty-six 1 2-m class ground-based telescopes Transiting Exoplanet Survey Satellite, we performed...
인공위성 궤도 결정을 위해 한국천문연구원의 0.6m 광시야 망원경을 이용하여 중 고궤도 인공위성과 폐기위성을 관측하였다. 관측 자료는 영상처리 및 좌표 보정을 통해 장착기기에 의한 오차를 보정한다. 위성 사료에서 얻은 정보는 시스템의 불안정성과 끝점 결정 오차에 의해 13각초의 가진다. KODAS의 결과로 시뮬레이션 좌표와 Gauss 방법을 이용해 예비궤도 수행하고 결정에 적합한 시간 간격을 찾아보았다. 또한 미분보정을 통한 결과의 향상을 확인하였다. 이들 결과를 평균궤도요소 형대로 변환하여 실제 자료와 비교하여 에비궤도 통해서 짧은 시간동안 위성의 추적이 가능함을 확인하였으며, 그 향상시킬 수 있음을 We used an optical observation system with a wide-field telescope and 5 computers in KASI (Korean Astronomy Space Science Institute) for satellite...
The objectives of this study are to analyze the satellite visibility at randomly established ground sites, determine five optimal sites perform optical surveillance and tracking domestic satellites, verify acquisition observation time sufficient maintain precise ephemeris that have been already determined. In order accomplish these objectives, we analyzed for sun-synchronous orbit low earth middle satellites as well continuous along with fictitious track, calculate effective visibility. For...
Optical observation system provides angle-only measurement for orbit determination of space object. Range can be directly acquired using laser ranging or tone system. Initial (IOD) by angle- only data set shows discrepancy according to the time interval. To solve this problem, range should added IOD. In study, two-site optical was used derive information. We have observed nine geostationary earth satellites The result accuracy over 99.5% compared results from satellite tool kit simulation....
An optical tracking system has advantages for observing geostationary earth orbit (GEO) satellites relatively over other types of observation system. Regular surveying unidentified space objects with the can be an early warning tool safety five Korean active GEO satellites. Two strategies positioning on observed image Communication, Ocean and Meteorological Satellite 1 are tested compared. Photometric method a half root mean square error against streak method. Also eccentricity initial...
We estimated the orbit of Communication, Ocean and Meteorological Satellite (COMS), a Geostationary Earth Orbit (GEO) satellite, through data from actual optical observations using telescopes at Sobaeksan Optical Astronomy Observatory (SOAO) Korea Space Science Institute (KASI), Wide field Patrol (OWL) KASI, Chungbuk National University (CNUO) August 1, 2014, to January 13, 2015. The astrometric satellite were extracted World Coordinate System (WCS) in obtained images, geometrically...
Abstract The Earth close approach of near-Earth asteroid 2005 LW3 on 2022 November 23 represented a good opportunity for second observing campaign to test the timing accuracy astrometric observation. With 82 participating stations, International Asteroid Warning Network collected 1046 observations around time approach. Compared previous targeting 2019 XS, some individual observers were able significantly improve their reported observation times. In particular, U.S. surveys achieved...
TLE로부터 SGP4/SDP4 모델을 이용하여 인공위성의 가상의 위치 정보를 얻은 후 Gauss 방법을 사용하여 예비궤도를 결정해보았다. 예비궤도 결정에 필요한 임의의 세 점 사이의 시간간격을 변화시켜 결과를 위성의 참값과 비교하여 최소의 차이를 가지는 관측 시간 간격을 찾아보았으며, 결정법의 성능을 비교, 분석하였다. 실제 인공위성 결과와의 비교를 위해서 한국천문연구원의 광시야 망원경을 GPS위성(PRN 26)과 무궁화 2호의 광학관측 데이터를 같은 방법으로 결정해 보았다. 정밀궤도결정을 위하여 시뮬레이션에서 얻어진 가지고 정밀케도결정을 수행하였으며, 데이터의 오차와 간격에 따라 수행하여 원하는 정밀도를 얻기 위한 시스템의 조건에 대해서 알아보았다. method for the initial orbit determination was tested using angle-only data obtained by propagation TLB and model.. As analysis...
Korea Astronomy and Space Science Institute (KASI) has been developing one mobile stationary SLR system since 2008 named as ARGO-M ARGO-F, respectively. KASI finished the step of deriving requirements ARGO. The include definitions scopes various software hardware components which are necessary for operation system. And define function, performance, interface requirements. consisting site, ARGO-F Remote Operation Center (ROC) inside is designed remote access automatic tracking control main...
An algorithm to automatically extract coordinate and time information from optical observation data of geostationary orbit satellites (GEO satellites) or geosynchronous (GOS is developed. The wide-field patrol system capable automatic using a pre-arranged schedule. Therefore, if this type analysis available, daily unmanned monitoring GEO can be possible. For acquisition for development, the COMS1 satellite was observed with 1-s exposure 1-m interval. images were grouped processed in terms...
As a governmentally approved domestic entity for Space Situational Awareness, Korea Astronomy and Science Institute (KASI) is developing operating an optical telescopes system, Optical Wide-field PatroL (OWL) Network. During the test phase of this it necessary to determine range brightness observable satellites. We have defined standard magnitude Low Earth Orbit (LEO) satellites calibrate their luminosity in terms parameters such as distance, angle, angular rate. In work, we report five LEO...
We conduct BVRI and R band photometric observations of asteroid (5247) Krylov from January 2016 to April for 51 nights using the Korea Microlensing Telescope Network (KMTNet). The color indices at light curve maxima are determined as <TEX>$B-V=0.841{\pm}0.035$</TEX>, <TEX>$V-R=0.418{\pm}0.031$</TEX>, <TEX>$V-I=0.871{\pm}0.031$</TEX> where phase angle is <TEX>$14.1^{\circ}$</TEX>. They acquired after standardization instrumental measurements ensemble normalization technique. Based on indices,...