• 천문학회지
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• 제43권5호
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• pp.169-181
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• 2010

We develop a proto-model of an off-axis reflective telescope for infrared wide-field observations based on the design of Schwarzschild-Chang type telescope. With only two mirrors, this design achieves an entrance pupil diameter of 50 mm and an effective focal length of 100 mm. We can apply this design to a mid-infrared telescope with a field of view of $8^{\circ}{\times}8^{\circ}$. In spite of the substantial advantages of off-axis telescopes in the infrared compared to refractive or on-axis reflective telescopes, it is known to be difficult to align the mirrors in off-axis systems because of their asymmetric structures. Off-axis mirrors of our telescope are manufactured at the Korea Basic Science Institute (KBSI). We analyze the fabricated mirror surfaces by fitting polynomial functions to the measured data. We accomplish alignment of this two-mirror off-axis system using a ray tracing method. A simple imaging test is performed to compare a pinhole image with a simulated prediction.

• 천문학논총
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• 제15권spc2호
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• pp.57-64
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• 2000

It is realized that the extraterrestrial matter is in ionized state, plasma, so the matter of this kind behaves as not expected because of its sensitiveness to electric and magnetic fields and its ability to carry electric currents. This kind of subtle change can be observed by an instrument for the magnetic field measurement, the magnetometer usually mounted on the rocket and the satellite, and based on the ground observatory. The magnetometer is a useful instrument for the spacecraft attitude control and the Earth's magnetic field measurements for the scientific purpose. In this paper, we present the preliminary design and the test results of the two onboard magnetometers of KARl's (Korea Aerospace Research Institute) sounding rocket, KSR­III, which will be launched during the period of 2001-02. The KSR-III magnetometers consist of the fluxgate magnetometer, MAG/AIM (Attitude Information Magnetometer) for acquiring the rocket flight attitude information, and of the search-coil magnetometer, MAG/SIM (Scientific Investigation Magnetometer) for the observation of the Earth's magnetic field fluctuations. With the MAG/AIM, the 3-axis attitude information can be acquired by the comparison of the resulting dc magnetic vector fields with the IGRF (International Geomagnetic Reference Field). The Earth's magnetic field fluctuations ranging from 10 to 1,000 Hz can also be observed with the MAG/SIM measurement.

• Journal of Astronomy and Space Sciences
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• 제18권3호
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• pp.219-230
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• 2001

원자외선 분광기 (Far ultraviolet IMaging Spectres.mph; FIMS)는 과학위성 1호의 주탑재체로 개발되고 있다. 원자외선 분광기 광학부에 대한 민감도 분석과 오차 예산 분석을 광범위하게 수행하였다. 몬테카를로 시뮬레이션을 통하여 제작 오차 및 조립 오차 등의 모든 오차가 함께 존재할 때 실제 원자외선 분광기가 갖게 되는 성능을 조사하였다. 시뮬레이션 결과 과학 임무를 위해 필요한 모든 요구 조건을 99.9% 이상의 확률로 만족하고 있음을 확인하였다.

• 천문학논총
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• 제30권2호
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• pp.645-647
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• 2015

We have initiated a Very Long Baseline Interferometer (VLBI) monitoring project of 36 methanol maser sources at 6.7 GHz using the Japanese VLBI Network (JVN) and East-Asian VLBI Network (EAVN), starting in August 2010. The purpose of this project is to systematically reveal 3-dimensional (3-D) kine-matics of rotating disks around forming high-mass protostars. As an initial result, we present proper mo- tion detections for two methanol maser sources showing an elliptical spatial morphology, G 002.53+00.19 and G 006.79-00.25, which could be the best candidates associated with the disk. The detected proper motions indicate a simple rotation in G 002.53+00.19 and rotation with expansion in G 006.79-00.25, respectively, on the basis of disk model fits with rotating and expanding components. The expanding motions might be caused by the magnetic-centrifugal wind on the disk.

• 천문학회지
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• 제36권spc1호
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• pp.125-133
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• 2003

New Jersey Institute of Technology (NJIT), in collaboration with the University of Hawaii (UH), is upgrading Big Bear Solar Observatory (BBSO) by replacing its principal, 65 cm aperture telescope with a modern, off-axis 1.6 m clear aperture instrument from a 1.7 m blank. The new telescope offers a significant incremental improvement in ground-based infrared and high angular resolution capabilities, and enhances our continuing program to understand photospheric magneto-convection and chromospheric dynamics. These are the drivers for what is broadly called space weather - an important problem, which impacts human technologies and life on earth. This New Solar Telescope (NST) will use the existing BBSO pedestal, pier and observatory building, which will be modified to accept the larger open telescope structure. It will be operated together with our 10 inch (for larger field-of-view vector magnetograms, Ca II K and Ha observations) and Singer-Link (full disk H$\alpha$, Ca II K and white light) synoptic telescopes. The NST optical and software control design will be similar to the existing SOLARC (UH) and the planned Advanced Technology Solar Telescope (ATST) facility led by the National Solar Observatory (NSO) - all three are off-axis designs. The NST will be available to guest observers and will continue BBSO's open data policy. The polishing of the primary will be done in partnership with the University of Arizona Mirror Lab, where their proof-of-concept for figuring 8 m pieces of 20 m nighttime telescopes will be the NST's primary mirror. We plan for the NST's first light in late 2005. This new telescope will be the largest aperture solar telescope, and the largest aperture off-axis telescope, located in one of the best observing sites. It will enable new, cutting edge science. The scientific results will be extremely important to space weather and global climate change research.

• Journal of Astronomy and Space Sciences
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• 제19권4호
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• pp.273-282
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• 2002

과학위성 1호의 주탑재체인 원자외선 분광기의 검출기 전자부에 대한 특성을 분석하였다. FIMS (Far-ultraviolet Imaging Spectrograph)는 교차 지연선 양극을 가진 MCP(micro-channel plate)를 사용하여 입사된 원자외선 광자의 위치를 검출한다. MCP에 입사하는 광자는 MCP을 통해 전자형태로 변환되고 증폭된다. 증폭된 전하운의 중심은 양분되어 연결된 지연선을 통해 양단으로 나가게 되고, 지연선의 양단에서 전하운의 도착시간 차이를 구하여 입사된 광자의 위치를 판독한다. FIMS의 경우 2개의 MCP 검출기를 갖고 있으며, 각각 25mm$\times$25mm의 유효 크기를 갖고있다. 또 신호처리계는 1채널의 신호처리 회로계를 통해 2개의 검출기에 대한 영상검출이 가능하도록 함으로써 신호처리계의 복잡성을 피하고 아울러 전력과 무게 비용을 줄였다. 이 시스템을 통해 높은 시간 및 공간 분해능(<$35{\times}75$ps FWHM)을 얻었으며, 6W 이하의 저전력 시스템을 구현하였다.