• Journal of Astronomy and Space Sciences
• /
• v.2 no.2
• /
• pp.69-99
• /
• 1985

The UBV observations of the Brightest RS CVn-type eclipsing binary star AR Lac were made at four observatories, two in Korean and two in the U.S. in the 1980-81 and 1981-82 seasons. As a result of the cooperation, two light curves in the yellow and in the blue were completed for each observing seasons. Ultraviolet observations were also made at three of the four observatories. The orbital period of AR Lac apparantly decreased around 1977. An analysis of our yellow light curves together with five other yellow curves available in the literature since 1975 shows that there seems no periodicity in the migration of the distortion waves. There is a gradual decrease of at least 0.m1 between 1976 and 1982 in the brightness of the cooler component if one assumes that the hotter component is constant.

• Acta Via Serica
• /
• v.4 no.2
• /
• pp.97-118
• /
• 2019

This study presents a new conceptualization of the history of Islamic astronomy. Islamic history is an embedded global cultural phenomenon and will be analyzed at different levels: a) the history of institutional aspects (observatories, including buildings), b) instruments, c) manuscripts, and d) scholars. This phenomenon will be analyzed as a multi-lingual phenomenon with Arabic as the language of sciences as a starting point. Although this is not a study of a geographical region in a narrow sense, it is a historical note on the entanglement of research written in Arabic, Persian and other languages and contextualized in a framework reaching geographically far beyond the confines of the Islamic world and being part of global history.

• The Bulletin of The Korean Astronomical Society
• /
• v.38 no.1
• /
• pp.26-26
• /
• 2013

The high Antarctic plateau is the driest and coldest environment on the surface of the Earth and offers superlative conditions for the conduct of a wide range of astronomical observations, from optical to millimetre wavebands. This includes, especially, the infrared - where the sky background is greatly reduced from temperate sites - and the sub-millimetre / THz bands - where new or cleaner atmospheric windows can be viewed through. Astronomical observations have now been conducted from five locations on the Antarctic plateau - the South Pole, Domes A, C and F, and Ridge A. Ambitious plans for the construction of observatories there have been announced. An IAU Symposium on "Astrophysics from Antarctica" featured as part of last year's IAU General Assembly in Beijing. This talk will provide an overview of astronomy in Antarctica, describing the special conditions that make some forms of observation particularly favourable there, and discuss the development of observatories on the Antarctic plateau and the plans for their future development.

• The Bulletin of The Korean Astronomical Society
• /
• v.38 no.1
• /
• pp.44.2-44.2
• /
• 2013

We probe the feasibility of high-frequency radio observations of very rapid flux variations in compact active galactic nuclei (AGN). Our study assumes observations at 230 GHz with a small 6-meter class observatory, using the SNU Radio Astronomical Observatory (SRAO) as example. We find that 33 radio-bright sources are observable with signal-to-noise ratios larger than ten. We derive statistical detection limits via exhaustive Monte Carlo simulations assuming (a) periodic, and (b) episodic flaring flux variations on time-scales as small as tens of minutes. We conclude that a wide range of flux variations is observable. This makes high-frequency radio observations - even with small observatories - a powerful probe of AGN intra-day variability; especially, those observations complement observations at lower radio frequencies with larger observatories like the Korean VLBI Network (KVN).

• The Bulletin of The Korean Astronomical Society
• /
• v.43 no.2
• /
• pp.29.3-29.3
• /
• 2018

Neutrino astronomy is now possible as the technology to detect neutrinos has been advancing. Current and planned neutrino-detecting facilities can be operated as a conventional telescope because they can measure the direction toward the celestial sources as well as their physical properties like energy. Together with gravitational wave, neutrino astronomy opens a new field of astronomy, often called, multi-messenger astronomy, which also involves "traditional" electro-magnetic-wave-detection-based astronomy. Expecting that Korean Neutrino Observatory (KNO) will be one of the best neutrino observatories when it is constructed, a group of Korean astronomers and astrophysicists formed a working group and began to investigate possible astronomical neutrino sources that could be detected by KNO and other neutrino observatories. This talk presents the recent activities of the working group and introduces the list of possible neutrino sources.

• Journal of The Korean Astronomical Society
• /
• v.38 no.2
• /
• pp.107-108
• /
• 2005

The situations and locations of the Asian astronomical observatories are overviewed. I propose to construct a medium size Infrared Telescope at a good site in the Asian district.

• The Bulletin of The Korean Astronomical Society
• /
• v.22
• /
• pp.10.2-10.2
• /
• 1997

• The Bulletin of The Korean Astronomical Society
• /
• v.30 no.1
• /
• pp.44.2-44.2
• /
• 2005

• The Bulletin of The Korean Astronomical Society
• /
• v.40 no.1
• /
• pp.52.3-53
• /
• 2015

The GMT-Consortium Large Earth Finder (G-CLEF) is a fiber-fed, optical band high dispersion echelle spectrograph that selected as the first light instrument for the Giant Magellan Telescope (GMT). This G-CLEF has been designed to be a general- purpose echelle spectrograph with the precisional radial velocity (PRV) capability of 10 cm/sec as a goal. The preliminary design review (PDR) was held on April 8 to 10, 2015 and the scientific observations will be started in 2022 with four mirrors installed on GMT. We have been participating in this preliminary design study in flexure control camera (slit monitoring system), calibration lamp sources, dichroic assembly and the fabrication of the proto-Mangin Mirror. We present the design concept on the parts KASI undertaken, introducing the specifications and capabilities of G-CLEF.

• Publications of The Korean Astronomical Society
• /
• v.30 no.2
• /
• pp.699-701
• /
• 2015

The high plateaus in west China may provide suitable sites for astronomical observations with the institute's middle-range telescopes and possibly with larger telescopes. Under China-Japan collaborations for site survey in west China, we have been conducting searches for good sites and monitoring their characteristics over several years. As recent results of our site survey show, sites in west Tibet are revealed with a high possibility of good astronomical observations. Weather characteristics at Gar in Ali, Tibet, show its high clear-sky ratios, especially in winter, comparable to Mauna Kea, Hawaii. But it has some wind problem in winter, where stronger wind speeds, over 20m/sec, occur frequently even though the sky is clear. To find calmer sites, we have conducted numerical simulations for the Ali area using the Japan Meteorological Agency NonHydrostatic Model. We have found another site, named ZoZo Hill, near Gar. We will continue to monitor the Gar site to clarify weather characteristics over the whole year and hopefully start to negotiate for site monitoring at ZoZo Hill this year.