• Journal of Space Technology and Applications
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• v.4 no.2
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• pp.105-120
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• 2024

The abilities of system engineering and project management (PM) are essential in the development of large instrumentations in modern astronomy. We propose a novel undergraduate educational program that allows students to gain experience in system engineering and PM by making a practical small spectrograph along with its test observation. A pilot program titled "Creative Astronomical Instrument Development and Observation" was conducted in Chungnam National University, as a part of the Space Expert Training Program of Ministry of Science and ICT during the Fall semester of 2023. After five teams were organized from 24 participating students, each team manufactured a spectrograph and observed spectra of the Sun, Moon, or planets with it. The development process was guided by several reviews, and students were evaluated based on the outcomes of their development processes and documentation. Through this program, students acquired fundamental principles of systems engineering and PM, as well as optical and mechanical engineering skills.

• Journal of the Korean earth science society
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• v.32 no.7
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• pp.902-912
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• 2011

The purpose of this study was to investigate the effects of teaching based on analysis of a hierarchy of the concepts associated with astronomical observation as well as each learner's status of knowledge through analytical methods of the knowledge state. A test instrument was developed to measure high school students' concepts associated with astronomical observation before instruction. The learners' psychological hierarchy associated with astronomical observation that the participants possessed showed the order of 'motion of the earth${\rightarrow}$coordinate system${\rightarrow}$astronomical observation (mechanism of the telescope${\rightarrow}$installation of the telescope${\rightarrow}$observation through the telescope)', and so was the hierarchy of teaching (70.6%). The learners' knowledge state that is supposed to be similar each other in the ability of observing celestial bodies was different even through they scored the same on the concept test. There were cases with the knowledge state well-structured and not well-structured, which suggests that differentiated instruction with appropriate teaching-learning prescriptions be prepared. An analysis of the knowledge state can play the role of both preparing individualized learning prescriptions and formative evaluation. In the unit dealing with astronomical observation of Earth ScienceI, teaching according to the psychological hierarchy of learners rather than the order in which the textbook syllabi were presented scored significantly higher (p<0.05) on the level of concept achievements. This result suggests that the teacher can help students achieve more efficient in learning by analyzing the learner's knowledge state and reordering the syllabi of the textbook in teaching the concepts associated with astronomical observation.

• The Bulletin of The Korean Astronomical Society
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• v.39 no.1
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• pp.52.2-52.2
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• 2014

The Immersion Grating Infrared Spectrometer (IGRINS) is an unprecedentedly minimized infrared cross-dispersed echelle spectrograph with a high-resolution and high-sensitivity optical performance. A silicon immersion grating features the instrument for the first time in this field. IGRINS will cover the entire portion of the wavelength range between 1.45 and $2.45{\mu}m$ accessible from the ground in a single exposure with spectral resolution of 40,000. Individual volume phase holographic (VPH) gratings serve as cross-dispersing elements for separate spectrograph arms covering the H and K bands. On the 2.7m Harlan J. Smith telescope at the McDonald Observatory, the slit size is $1^{\prime\prime}{\times}15^{\prime\prime}$. IGRINS has a $0.27^{\prime\prime}$ pixel-1 plate scale on a $2048{\times}2048$ pixel Teledyne Scientific & Imaging HAWAII-2RG detector with SIDECAR ASIC cryogenic controller. The instrument includes four subsystems; a calibration unit, an input relay optics module, a slit-viewing camera, and nearly identical H and K spectrograph modules. The use of a silicon immersion grating and a compact white pupil design allows the spectrograph collimated beam size to be 25mm, which permits the entire cryogenic system to be contained in a moderately sized rectangular vacuum chamber. The fabrication and assembly of the optical and mechanical hardware components were completed in 2013. In this presentation, we describe the major design characteristics of the instrument and the early performance estimated from the first light commissioning at the McDonald Observatory.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.1
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• pp.52.1-52.1
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• 2015

We have recently installed SQUEAN on the 82 inch telescope at the McDonald Observatory, USA. This instrument consists of an ANDOR CCD camera, a focal reducer, an electronic box, an auto guiding system and a new filter wheel which holds up to 20 filters. Currently the filter wheel is equipped with Johnson-Cousins BVRI filters, SDSS rizY and isiz filters, and 50nm medium band pass filters (M625(625nm), M675(675nm), M725(725nm), M775(775nm), M825(825nm), M875(875nm), M925s(925nm), M975(975nm), and M1025(1025nm)). Our medium band pass filter system is suitable with SED fitting. Filter transformation methods are essential for time-domain observations including transient objects, e.g., supernovae, variable stars, and solar system bodies. In this work, we develop a series of equations to convert the open clusters photometry data within these filter systems.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.1
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• pp.81.1-81.1
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• 2015

FIMS/SPEAR is a dual-channel far-ultraviolet imaging spectrograph on board the Korean microsatellite STSAT-1, which was launched on 2003 September 27. While the instrument is optimized for the observation of diffuse emissions, it was able to observe a number of bright stars without much contamination from the diffuse background or other faint stars. In this paper, we present a catalog of the far-ultraviolet spectra for 543 stars observed by FIMS/SPEAR during its mission lifetime of a year and a half, covering over the 80% of the sky. Of these, 296 stars were also observed by the International Ultraviolet Explorer (IUE), which covered a wide spectral band including the FIMS wavelength band (1370--1710 A). The stellar spectral types involved in the catalog span from B0 to A3. We compare the new spectra with those of IUE when they are available, and discuss some examples. We also revised the effective area of FIMS that the FIMS stellar spectra are consistent with the IUE spectra.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.1
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• pp.45.1-45.1
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• 2015

Galaxy clusters have provided important information to understand the evolution of the universe, since the number density and mass of clusters are tightly related to the cosmological parameters. In addition, galaxy clusters are an excellent laboratory to investigate the galaxy evolution in dense environments. However, finding galaxy clusters at high redshift ($z{\geq}1$) still remains as a main subject in astronomy due to their rareness and difficulty in identifying such objects from optical imaging data alone. Here, we report a spectroscopic follow-up observation of distant galaxy cluster candidates identified by a deep optical-NIR dataset of Infrared Medium-deep Survey. Through the galaxy spectra taken with the IMACS instrument on the Magellan telescope, we confirm at least 3 massive clusters at z~0.92. Interestingly, the maximum spatial separation between these clusters is ~8Mpc, which implies that this system is a new supercluster in the distant universe. We also discuss properties of galaxies in these clusters based on multi-wavelength photometric data.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.1
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• pp.42.1-42.1
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• 2015

Accurately estimating black hole (BH) masses at high redshifts is imperative in the current and future era of large-area extragalactic spectroscopic surveys. We present an extension of existing comparisons between rest-frame UV and optical virial BH mass estimators to intermediate redshifts, lower luminosities, and lower BH masses, comparable to the local $H{\beta}$ reverberation-mapping sample. We use data from the AGES survey and also newly acquired near-infrared spectra from the FMOS instrument on Subaru telescope for 89 broad-lined active galaxies at redshifts between 0.5 and 1.6. We focus on the MgII, CIV, and CIII broad emission lines and compare them to both $H{\alpha}$ and $H{\beta}$, using two different prescriptions to describe their emission profile width. We confirm that MgII shows a tight correlation with $H{\alpha}$, with a scatter of ~0.25 dex. The CIV and CIII estimators can be considered viable virial mass estimators, despite large scatter values. We combine our dataset with previous high redshift and high luminosity CIV and CIII measurements from the literature and we calculate a scatter of $\sim0.4$ dex and an offset to the 1:1 relation consistent with 0 for the combined sample. This updated comparison spans a total of 4 decades in BH mass, a much wider range than any previous individual study.

• Journal of The Korean Astronomical Society
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• v.38 no.2
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• pp.69-72
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• 2005

The FIMS (Far-ultraviolet IMaging Spectrograph; also known as SPEAR, Spectroscopy of Plasma Evolution from Astrophysical Radiation) is the primary payload of the STSAT-1, the first Korean science satellite, which was launched in September, 2003. The FIMS performs spectral imaging of diffuse far-ultraviolet emission with the unprecedented wide field of view and the relatively good spectral resolution. We present far-ultraviolet spectral observations of highly ionized interstellar medium including supernova remnants, superbubbles, soft X-ray shadows, and the molecular hydrogen fluorescent emission lines. The FIMS has detected He II, C III, 0 III, O IV, Si IV, O VI, and $H_2$ fluorescent emission lines. The emission lines arise in shocked or thermally heated and in photo-ionized gases. We present an overview of the FIMS instrument and its initial observational results.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.2
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• pp.27.2-27.2
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• 2015

Strategic plan of Subaru science and operation will be introduced. Currently, Subaru has wide variety of instruments, conducts only classical observations, with less than 5 nights allocation for each proposal. Near future, Subaru will emphasize on surveys, introduce queue mode observations, reduce the number of instruments, and concentrate on large size programs. Large surveys are called Subaru Strategic Programs (SSPs). HSC-SSP is on-going (300 nights for 5 years), PFS-SSP will start at around 2020 (360 nights for 5 years), and IRD-SSP from 2016 (TBD). HSC science includes 1) cosmology with gravitational lensing, 2) lensing studies of galaxies and clusters, 3) photometric redshifts, 4) the Solar system, 5) the Milky Way and the Local Group, 6) AGN/quasars, 7) transients, 8) galaxies at low/high redshifts, and 9) clusters of galaxies. PFS science includes 1) cosmology, 2) galaxy & AGN, and 3) galactic archaeology. Subaru is planning the third pillar instrument, so called ULTIMATE-Subaru, which is the GLAO optical-NIR wide field camera & multi-IFU spectrograph for finding galaxies at ultra high redshift (z>10). Finally the strategy from Subaru to TMT will be presented. Subaru will conduct four major SSPs (HSC, PFS, IRD, ULTIMATE-Subaru) in coming decade to provide targets to TMT. HSC performs wide field surveys to reveal the distribution of dark matter in the Universe. IRD surveys Earth-like young planets to discover ~20 Earth-like habitable planets. PFS studies the expanding Universe to provide a few million emission line galaxies to TMT.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.2
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• pp.56.1-56.1
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• 2015

The GMT-Consortium Large Earth Finder (G-CLEF) is the very first light instrument of the Giant Magellan Telescope (GMT) and an optical-band echelle spectrograph. The Flexure Control Camera (FCC) is one of the major contributions of KASI's for the spectrograph project. FCC system includes the Fiber Mirror monitoring and the on- and off-slit mode auto-guidance algorithm. In this study, we present the modified design of the FCC optics and opto-mechanics after the G-CLEF Preliminary Design Review (PDR) held in Cambridge in April 2015.