• Journal of The Korean Astronomical Society
• /
• v.36 no.1
• /
• pp.43-48
• /
• 2003

We introduce and describe performance of the 6-meter telescope of Seoul Radio Astronomy Observatory (SRAO). All the softwares and instruments except the antenna structure and its driving system are developed for ourselves. The SIS mixer type receiver resulted in the receiver noise temperature less than 50 K (DSB) over the whole 3-mm radio window. An autocorrelation spectrometer, developed first in Korea, provides maximum 50 MHz band width over 1024 channels. Antenna surface is measured and adjusted using template method and radio holography which resulted in a superb surface accuracy bet-ter than 30${\mu}m$. Accordingly, the aperture and beam efficiences amount to $70\%$ and $75\%$, respectively, largely independent of frequency in the 85 - 115 GHz range. It is also found that telescope pointing errors are less than 10" in both azimuth and elevation and that antenna gain is almost constant against elevation greater than $20^{\circ}$, without adjusting sub-reflector position. The SRAO 6-meter telescope is now fully operational and all these characteristics verify that observations are carried out with high precision and fidelity.

• Journal of The Korean Astronomical Society
• /
• v.38 no.2
• /
• pp.311-314
• /
• 2005

We report the current status of Japanese lunar exploration SELENE (SELenological and ENgineering Explorer). As of the end of 2004, scientific instruments onboard the Main Orbiter are under final checkout before they are provided to the proto-flight-model (PFM) integration test. Also, we present the future perspectives of the lunar based instruments and facilities. 'In-situ Lunar Orientation Mea-surement (ILOM)' experiment measures the lunar rotation with high accuracy by tracking stars on the Moon with a small photo-zenith-tube type optical telescope. A basic idea of a radio telescope array of very low frequency range on the lunar far-side is also mentioned.

• Journal of The Korean Astronomical Society
• /
• v.44 no.3
• /
• pp.81-87
• /
• 2011

We carry out 100-GHz band test observations with the newly-constructed KVN 21-m radio telescopes in order to evaluate their performance. The three telescopes have similar performance parameters. The pointing accuracies are about 4" rms for the entire sky. The main beam sizes are about 30" (FWHMs), which is nearly the diffraction limit of the telescopes at the observing frequency (97 GHz). The measured aperture and main-beam efficiencies are about 52% and 46%, respectively, for all three telescopes. The estimated moon efficiency is ~84% for the KVN Tamna telescope. The first sidelobes appear 50" (~1.6${\times}$FWHM) from the main beam centers and the levels are on average -14 dB.

• The Bulletin of The Korean Astronomical Society
• /
• v.35 no.2
• /
• pp.36.1-36.1
• /
• 2010

The Redshift Search Receiver (RSR) is a sensitive, ultra-wideband spectrometer that is being built at the University of Massachusetts as one of the facility instruments for the 50-m Large Millimeter Telescope (LMT). It consists of four receivers each covering the entire 3 mm window from 74 to 111 GHz instantaneously. The primary goal of the receiver is to detect multiple molecular lines in galaxies at any distance and uniquely determine the redshift, in particular dust-obscured star forming systems at high-z which are not easily accessible. I will present some results from commissioning of the RSR on the Five College Radio Astronomy Observatory 14-m telescope, and discuss the future of the receiver.

• Journal of Astronomy and Space Sciences
• /
• v.18 no.2
• /
• pp.145-152
• /
• 2001

For the research of solar EUV (extreme ultraviolet) radiation, we have designed a small-sifted engineering model of solar EUV telescope, which is suitable for a Korean satellite. The EUV sole. telescope was designed to observe the sun at $584.3AA$(He I) and $629.7AA$(OV) The optical system is an f/8 Ritchey-Chr rien, and the effective diameter and focal length are 80mm and 640mm, respectively. The He I and 0V filters are loaded in a filter wheel. In the detection part, the MCP (Microchannel Plate) type is Z-stack, and the channel-to-diameter radio is 40:1. MCP and CCD are connected by fiber optic taper. A commercial optical design software is used for the analysis of the optical system design.