• Title, Summary, Keyword: spectrograph

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DESIGN AND MANUFACTURING OF THE CASSEGRAIN INTERFACE MODULE OF THE BOAO ECHELLE SPECTROGRAPH

  • KIM KANG-MIN;JANG BE-HO;HAN INWOO;JANG JEONG GYUN;SUNG HYUN CHUL;CHUN MOO-YOUNG;HYUNG SIEK;YOON TAE-SEOG;VOGT STEVEN S.
    • Journal of The Korean Astronomical Society
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    • v.35 no.4
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    • pp.221-227
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    • 2002
  • Cassegrain interface module (CIM) of the fiber-fed high resolution echelle spectrograph has been designed and manufactured for the 1.8 m reflector at the Bohynsan Optical Astronomy Observatory. We also constructed a long slit spectrograph attached to this CIM, which would replace the earlier rather inefficient medium dispersion spectrometer. We present detailed description for design and manufacturing concepts of the CIM which consists of a slit assembly, slit monitoring system, calibration lamp system and a long slit spectrograph, in order to provide how the overall system and each part. are constructed. The preliminary performance test carried out so far seems to indicate a successful result.

DEVELOPMENT STATUS OF THE DOTIFS DATA SIMULATOR AND THE REDUCTION PACKAGE

  • CHUNG, HAEUN;RAMAPRAKASH, A.N.;PARK, CHANGBOM
    • Publications of The Korean Astronomical Society
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    • v.30 no.2
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    • pp.675-677
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    • 2015
  • A data simulator and reduction package for the Devasthal Optical Telescope Integral Field Spectrograph (DOTIFS) has been developed. Since data reduction for the Integral Field Spectrograph (IFS) requires complicated procedures due to the complex nature of the integral spectrograph, common reduction procedures are usually not directly applicable for such an instrument. Therefore, the development of an optimized package for the DOTIFS is required. The data simulator observes artificial object and simulates CCD images for the instrument considering various effects; e.g. atmosphere, sky background, transmission, spectrograph optics aberration, and detector noise. The data reduction package has been developed based on the outcomes from the DOTIFS data simulator. The reduction package includes the entire processes for the reduction; pre-processing, flat-fielding, and sky subtraction. It generates 3D data cubes as a final product, which users can use for science directly.

Derivation of the Ambient Nitrogen Dioxide Mixing Ratio over a Traffic Road Site Based on Simultaneous Measurements Using a Ground-based UV Scanning Spectrograph

  • Lee, Han-Lim;Noh, Young-Min;Ryu, Jae-Yong;Hwang, Jung-Bae;Won, Yong-Gwan
    • Journal of the Optical Society of Korea
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    • v.15 no.1
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    • pp.96-102
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    • 2011
  • Simultaneous measurements using a scanning spectrograph system and transmissometer were performed for the first time over an urban site in Gwangju, Korea, to derive the ambient $NO_2$ volume mixing ratio. The differential slant column densities retrieved from the scanning spectrograph system were converted to volume mixing ratios using the light traveling distance along the scanning line of sight derived from the transmissometer light extinction coefficients. To assess the performance of this system, we compared the derived $NO_2$ volume mixing ratios with those measured by an in situ chemiluminescence monitor under various atmospheric conditions. For a cloudless atmosphere, the linear correlation coefficient (R) between the two data sets (i.e., data derived from the scanning spectrograph and from the in situ monitor) was 0.81; the value for a cloudy atmosphere was 0.69. The two sets of $NO_2$ volume mixing ratios were also compared for various wind speeds. We also consider the measurement errors, as estimated from an error propagation analysis.

PERFORMANCE TEST OF THE BOAO MEDIUM DISPERSION SPECTROGRAPH (MDS) (보현산천문대 중분산분광기의 성능 분석)

  • KIM KANG-MIN;KIM YEOJEONG;YOON TAE SEOG
    • Journal of The Korean Astronomical Society
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    • v.34 no.1
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    • pp.41-45
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    • 2001
  • We tested the characteristics of the BOAO Medium Dispersion Spectrograph (MDS) such as the CCD capabilities, wavelength shift by gravity direction variation, slit illumination function and efficiency. Then we calculated the appropriate exposure time to obtain the given S/N ratio for several given magnitudes. Also the remaining problems to be improved were discussed.

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Science with the Giant Magellan Telescope Integral-Field Spectrograph

  • Lee, Jae-Jun;Park, Byeong-Gon;Hwang, Na-Rae;Lee, Jun-Hyeop
    • The Bulletin of The Korean Astronomical Society
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    • v.38 no.1
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    • pp.68.2-68.2
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    • 2013
  • The Giant Magellan Telescope Integral-Field Spectrograph (GMTIFS) is a near-infrared imager and integral-field spectrograph, which will be the workhorse adaptive-optics (AO) instrument on the GMT when AO operations begin. We will describe the current design and proposed capabilities of the GMTIFS. We will also present a brief overview of GMTIFS science cases that include first-light objects, galaxy feedback and assembly, the nature of compact massive objects as well as the formation and evolution of stars and planets.

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PERFORMANCE TEST OF THE BOAO LONG SLIT SPECTROGRAPH (LSS) (보현산천문대 긴슬릿 분광기의 성능 분석)

  • Kim, Kang-Min;Lee, Byeong-Chul;Han, In-Woo;Yoon, Tae-Seog
    • Publications of The Korean Astronomical Society
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    • v.18 no.1
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    • pp.81-86
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    • 2003
  • We tested the characteristics of the newly made Long Slit Spectrograph (LSS) of the BOAO which replaced the Medium Dispersion Spectrograph (MDS) in the year of 2003. Performance test results on the spectrogram shift by gravity direction variation, slit illumination function, efficiency and the precision of the radial velocity measurements show the capabilities of the LSS are much improved in every respect comparing with those of the MDS.

Introduction of High Resolution Spectrograph by using Optical Freauency Comb.

  • Han, In-Woo;Kim, Kang-Min;Yoon, Tai-Hyun
    • The Bulletin of The Korean Astronomical Society
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    • v.35 no.1
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    • pp.36.1-36.1
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    • 2010
  • OFC (Optical Frequency Comb) is an optical spectrum which consists of equidistant lines in frequency space. OFC can thus be used as an optical ruler. Since it was demonstrated in late 1990s, it is revolutionizing many fields in frequency metrology such as the measurement of absolute optical frequencies, the measure ratios of optical frequencies with extremely high precision. It is also used in high-precision spectroscopy. In astronomy, OFC can be used as a very accurate and stable wavelength standard for a high resolution spectrograph to measure the radial velocity of celestial bodies with extremely high accuracy of about several tens cm/s. In our presentation, we will introduce some basic concepts of OFC and some issues to use it in astronomical spectrograph. We will also present our plan to develop a high resolution spectrograph with OFC.

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OPTICAL DESIGN OF FIMS TYPE FAR ULTRAVIOLET SPECTROGRAPH FOR SPACE OBSERVATION (FIMS 타입의 우주관측용 원자외선분광기 광학설계)

  • SEON KWANG-IL;YUK IN-SOO;RYU KWANG-SUN;LEE DAE-HEE
    • Publications of The Korean Astronomical Society
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    • v.19 no.1
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    • pp.65-70
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    • 2004
  • An imaging spectrograph concept optimized for extended far-ultraviolet emission sources is presented. Although the design was originally developed for FIMS aboard the first Korean science satellite STSAT-l launched on September 27, 2003, no rigorous theoretical background of the spectrograph design has been published. The spectrograph design employs an off-axis parabolic cylinder mirror in front of a slit that guides lights to a diffraction grating. The concave grating provides moderate spatial resolution over a large field of view. This mapping capability is absent in most astronomical instruments but is crucial to the understanding of the nature of a variety of astrophysical phenomena. The aberration theory presented in this paper can be extended to holographic gratings in order to improve the spatial as well as the spectral resolutions.

SPECTRA OF REFLECTED SUNLIGHT FROM PLANETS

  • LEE, DONG-EUN;SONG, IN-OK
    • Publications of The Korean Astronomical Society
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    • v.30 no.2
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    • pp.767-768
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    • 2015
  • Spectra of reflected sunlight from Mars and Jupiter are presented. They were obtained from an educational 1-D array spectrograph covering almost a full range of visible wavelengths, 200~900 nm with 1 nm spectral resolution. The question was whether a spectral difference could be obtained between that of terrestrial planets and gas planets with an educational spectrograph. It was installed in a 12-inch reflecting telescope at the Korea Science Academy of KAIST in Busan. Both spectra show clear absorption lines of reflected sunlight. They shows differences oin line presence, but are not very significant. This work means that the spectrograph successfully observed the reflected spectra of planets and can detect differences in spectra in terms of the absence and presence of absorption lines of planets.