• Publications of The Korean Astronomical Society
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• v.18 no.1
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• pp.87-95
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• 2003

FIMS (Far-ultraviolet IMaging Spectrograph) is the main payload of STSAT-1 satellite which was successfully launched on September 27, 2003. The optical system of FIMS consists of two sets of parabolic cylinder mirror, slit, ellipsoidal reflection grating, and baffle system. We designed two types of baffle system for the FIMS: FOV baffle and order baffle. FOV baffle in the mirror house controls the field of view, and the order baffle in the vacuum box blocks the rays reflected rays by different orders.

• 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.

• The Bulletin of The Korean Astronomical Society
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• v.35 no.1
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• pp.71.2-71.2
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• 2010

Cooling hot gas sets a floor on the ionization level for diffuse gas in the ISM in general and the galactic halo. Many high galactic latitude sight lines, cooling hot gas is the dominant source of the ionization. Such sites are prime regions for the formation of both C IV and Si IV ions at a temperature of T~105K. To study of the ISM that have the 104.5~6K ionization state by ionization or photoionization by the collision, searching for the radiation energy that is emitted at far ultra violet range is required. In this paper, we report the analysis of NGP( North Galactic Pole, $l:270^{\circ},b:90^{\circ},rad:40^{\circ}$) region by fuv($1350{\sim}1750{\AA}$) data that are surveyed with FIMS. After making the FIMS FUV image of the NGP region, we divided up into 50 small regions for that and got the spectrum emission lines from each one.

• The Bulletin of The Korean Astronomical Society
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• v.35 no.2
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• pp.70.2-70.2
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• 2010

Cooling hot gas sets a floor on the ionization level for diffuse gas in the ISM in general and the galactic halo. Many high galactic latitude sight lines, cooling hot gas is the dominant source of the ionization. Such sites are prime regions for the formation of both C IV and Si IV ions at a temperature of T~105K. To study of the ISM that have the 104.5~6K ionization state by ionization or photoionization by the collision, searching for the radiation energy that is emitted at far ultra violet range is required. In this paper, we report the analysis of NGP(North Galactic Pole, $l:0^{\circ},b:90^{\circ}$,rad: $40^{\circ}$) region by fuv($1350\sim1750\AA$) data that are surveyed with FIMS. After making the FIMS FUV image of the NGP region, we divided up into some small regions for that and got the spectrum emission lines from each one.

• Journal of Astronomy and Space Sciences
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• v.21 no.4
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• pp.391-398
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• 2004

Far-ultraviolet Imaging Spectrograph (FIMS) is the main payload of the Korea's first scientific micro satellite STSAT-1, which was launched at Sep. 27 2003 successfully. Major objective of FIMS is observing hot gas in the Galaxy in FUV bands to diagnose the energy flow models of the interstellar medium. Supernova remnants, molecular clouds, and Aurora emission in the geomagnetic pole regions are specific targets for pointing observation. Although the whole system was calibrated before launch, it is essential to perform on-orbit calibration for data analysis. For spectral calibration, we observed airglow lines in the atmosphere since they provide good spectral references. We identify and compare the observed airglow lines with model calculations, and correct the spectral distortion appeared in the detector system to improve the spectral resolution of the system.

• Journal of Astronomy and Space Sciences
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• v.19 no.4
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• pp.273-282
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• 2002

We describe some performance of the detector electronics system for the FIMS (Far-ultraviolet Imaging Spectrograph) mission. The FIMS mission to map the far ultraviolet sky uses MCP (micro-channel plate) detectors with a crossed delay line anode to record photon arrival events. FIMS has two MCP detectors, each with a ~25mm$\times$25mm active area. The unconventional anode design allows for the use of a single set of position encoding electronics for both detector fields. The centroid position of the charge cloud, generated by the photon-stimulated MCP, is determined by measuring the arrival times at both ends of the anode following amplification and external delay. The temporal response of the detector electronics system determines the readout's positional resolution for the charge centroid. High temporal resolution (<$35{\times}75$ps FWHM) and low power consumption (< 6W) were achieved for the FIMS detector electronics system.

• Bulletin of the Korean Space Science Society
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• 2004.04a
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• pp.99-99
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• 2004

We detected and analyzed molecular hydrogen fluorescence in the Taurus Cloud using the Far-ultraviolet Imaging Spectrograph (FIMS) on the STSAT-1 which was launched at SeP. 27 2003. FIMS is optimized for observing diffuse emission lines in the interstellar medium in the wavelength bands of 900-l150 and 1300-1700 angstrom. The Taurus region is a local molecular cloud which is good for studying molecular hydrogen fluorescence emissions. (omitted)

• The Bulletin of The Korean Astronomical Society
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• v.25 no.2
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• pp.22-22
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• 2000

• Journal of the KSME
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• v.41 no.6
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• pp.53-57
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• 2001

• Journal of Astronomy and Space Sciences
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• v.21 no.4
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• pp.383-390
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• 2004

We describe the in-flight sensitivity calibration of the Far ultraviolet Imaging Spectrograph (FIMS, also known as SPEAR) onboard the first Korean science satellite, STSAT-1, which was launched in September 2003. The sensitivity calibration is based on a comparison of the FIMS observations of the hot white dwarf G191B2B, and two O-type stars Alpha-Cam, HD93521 with the HUT (Hopkins Ultraviolet Telescope) observations. The FIMS observations for the calibration targets have been conducted from November 2003 through May 2004. The effective areas calculated from the targets are compared with each other.