The IGRINS is a near infrared high resolution spectrograph jointly developed by the Korea Astronomy and Space Science Institute and the University of Texas at Austin. We present design and fabrication of the optomechanical mount for the five mirrors, i.e., an input fold mirror, a slit mirror, a dichroic, and two camera fold mirrors. Based on the structure analysis and the thermal analysis of finite element methods, the optomechanical mount scheme satisfies the mechanical and the thermal design requirements given by the optical tolerance analysis. The performance of the fabricated mirror mounts has been verified through three IGRINS commissioning runs.

The KASINICS (Korea Astronomy and Space science Institute Near Infrared Camera System) is a ground-based near-infrared (NIR) imaging instrument. KASINICS has offner relay optics to reduce unwanted infrared light. For the offner optics, we adopted an ultra precision machining process which is installed at KBSI (Korea Basics Science research Institute). Since the offner relay optics is made of aluminum 6061 metal material, we did several tests to reach the specification. We found that a 0.497mm radius nose bite and 220m/min machining speed are best tool and condition to make this offner optics with the precision machine. In this paper, we report the technical method of ultra precision machining and results of the KASINICS offner optics.

We have developed a control electronics system for an infrared detector array of KASINICS (KASI Near Infrared Camera System), which is a new ground-based instrument of the Korea Astronomy and Space science Institute (KASI). Equipped with a 512×512 InSb array (ALADDIN III Quadrant, manufactured by Raytheon) sensitive from 1 to 5μm, KASINICS will be used at J, H, Ks, and L-bands. The controller consists of DSP(Digital Signal Processor), Bias, Clock, and Video boards which are installed on a single VME-bus backplane. TMS320C6713DSP, FPGA(Field Programmable Gate Array), and 384-MB SDRAM(Synchronous Dynamic Random Access Memory) are included in the DSP board. DSP board manages entire electronics system, generates digital clock patterns and communicates with a PC using USB 2.0 interface. The clock patterns are downloaded from a PC and stored on the FPGA. UART is used for the communication with peripherals. Video board has 4 channel ADC which converts video signal into 16-bit digital numbers. Two video boards are installed on the controller for ALADDIN array. The Bias board provides 16 dc bias voltages and the Clock board has 15 clock channels. We have also coded a DSP firmware and a test version of control software in C-language. The controller is flexible enough to operate a wide range of IR array and CCD. Operational tests of the controller have been successfully finished using a test ROIC (Read-Out Integrated Circuit).

The KASINICS (KASI Near Infrared Camera System) is a ground-based Near-Infrared (NIR) imaging instrument developed by the Korea Astronomy and Space Science Institute (KASI). In this paper, we report the test results of the KASINICS camera optics system which is comprised of a 1-1 Offner relay. We measure that the surface RMS fluctuations of the Offner mirrors are at the level of 10−1−10−2 of the target wavelengths, showing that the mirrors are sufficiently smooth for NIR observations. The alignment of the Offner optics system has been checked too. Our ray-tracing simulations find that the image quality should not degrade more than the pixel size of the KASINICS ( 40μm), if a de-centering or a tilt of the Offner mirrors are within 5mm, or 2.5° . Our measurement shows that the de-centering or the tilt of the Offner mirrors are less than 1 mm or 0.5° , assuring that the KASINICS image quality are not affected by the alignment errors. We have also measured that the optics resolution is 20μm and it does not degrade more than 10% over the detector surface area of 14.3 mm / times 14.3mm. Overall, we conclude that the KASINICS optics system satisfies the design requirements for NIR imaging observations.

The reimaging optics of the KASINICS (KASI Near Infrared Camera System) includes many transparent components like an entrance window, band-pass filters, and blocking filters. As observational targets or in-field background objects, bright stars may cause optical ghosts that can significantly degrade the system performance of the KASINICS. We estimated analytically the relative brightness of ghost components with respect to a point source and examined the effects of tilting optical components as a method of suppressing ghosts. We also performed numerical ray tracings including all the optical components and found the results are consistent with those of the analytic estimations. We conclude that the KASINICS will not suffer from significant ghost effects with appropriate anti-reflection coatings and fittings for the optical components.

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 H2 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.

We have developed a tool for measuring optical aberrations of telescope. We adopt curvature sensing technique and use the least square method for finding the amplitudes of the Zernike polynomials. This tool runs under the PC Linux system and the PC windows system with Linux emulators such as Cygwin. The program for UNIX system is used for optical alignment of 1.8M optical telescope at the Bohyunsan Optical Astronomical Observatory (BOAO) and the PC based program is used for the Korea Astronomy Observatory (KAO) wide field telescope (named NEOPAT-3). Our tool is found to be efficient for precise measurement of the optical aberrations of telescopes.

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.

We have developed a seeing monitoring system and measured seeing variation of the Bohyunsan Optical Astronomy Observatory (BOAO) and the Sobaeksan Optical Astronomy Observatory (SOAO) using a small telescope system. Our seeing monitoring system is similar to the differential image motion monitor (DIMM) installed at the ESO. The ooly difference between the BOAO and the SOAO seeing monitoring system is a detector system, a video camera at the BOAO and ST-4 camera at the SOAO. We confirmed that the seeing monitoring system at the SOAO can measure average seeing size inspite of its simple detector system. From the BOAO seeing measurement, we found that the seeing size changes fast. We expect that our seeing monitoring system could be used for real time seeing monitoring after some improvement, and the data to be obtained would be very useful when we build adaptive optic system in the future.

We present the characteristics of the 2K CCD camera at the Bohyunsan Optical Astronomy Observatory of the Korea Astronomy Observatory at the time of its development. The purpose of this paper is to support the observers who may need detailed information on the characteristics of the camera and to provide helpful information on the optimization' of a CCD camera for those who try to develop their own camera. The 2K CCD camera was optimized to have a gain of 1.8e−/ADU and a read out noise of 7e− from an experiment using radioactive 55 Fe X-ray source. The charge transfer efficiency was measured as 0.9999976 for serial and 0.9999942 for parallel direction, which means 0.5% charge loss along the serial direction and 1.2% along the parallel direction across the chip. The quantum efficiency of the camera was measured from an experiment using a homogeneous light source consisting of a halogen lamp and an integrating sphere with a monochromator. The resulting quantum efficiency of the camera peaked at the wavelength range 600-700 nm with the value of ＼-0.89 .