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        검색결과 4

        1.
        2005.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Sprites, elves and blue jets are collectively denominated as the upper atmospheric transient luminous events (TLEs). They are recently discovered optical flashes between active thunderstorms and the ionosphere. In this report, a brief introduction to the most important characteristics of TLEs is given. Since 2001, scientists from the National Cheng Kung University have been performing yearly summer campaigns from various locations in Taiwan. The main achievements of their yearly campaign are presented.
        3,000원
        2.
        1996.12 KCI 등재 SCOPUS 구독 인증기관·개인회원 무료
        Speckle Interferometer equipped with an ITT intensified CCD have been used on the NCUO ( National Central University Observatory, Taiwan) 24-inch telescope for studying the orbits of bright binary systems selected from the Yale's Bright Star Catalogue. The high resolution and high sensitivity ITT intensified solid state video camera ( F4577 ) has external gain and gate control functions which will simplify the design of the speckle camera and allow us to do precise speckle photometry. The goal of this project is trying to study the bright binary systems with separations between the average size of seeing disk and the diffraction limit of the 24-inch telescope. Recently some observing data have been reduced and compared with the other teams' results. We are now improving the data reduction technology and trying to use real time observing mode on the monthly routine observation.
        3.
        1996.12 KCI 등재 SCOPUS 구독 인증기관·개인회원 무료
        We present a new photometric study of the globular cluster NGC288 in Stromgren u, v, b, y, and Hβ system. This cluster is known to have an intermediate metallicity but its color-magnitude diagram has a pure blue horizontal branch, which is a signature of metal poor stellar population. We compare our dataset with Bergbusch's (1993) in both field size and CMD to see whether different photometry system would determine the same physical parameters of a cluster. Demarque and Yi's isochrones (1996, private communication) were applied to Bergbusch's dataset, and we obtained distance modulus of (m - M) = 14.9 ± 0.2, color excess of E(B - V) = 0.03, and age of 1.5±3 Gyr. Vandenberg's (1985) isochrones for Stromgren system were also applied to Bergbusch's and our data. We find that the isochrone fits to different photometric systems give rather in consist ant solutions. The source of this discrepancy may become clear when the Demarque and Yi's isochrones for Johnson system are converted to those of Stromgren system. We note that Kurucz model atmospheres provide a useful ground for this conversion work as well as theoretical study of Stromgren characteristics of globular cluster stars.
        4.
        1996.12 KCI 등재 SCOPUS 구독 인증기관·개인회원 무료
        Snapshots of eight SA and standard fields from low to high galactic latitudes were made using the KPNO 0.9m 2K × 2K CCD with a limiting magnitude from 19 to 22.5. The purpose of this study is to determine the vertical distribution of stars with respect to Galactic latitude and z-distance in comparison with the model simulation between intermediate population to the 'thick disk' component of scale height of a few kpc. Comparison of the preliminary results between observed and model simulation for 3 of the S fields shows good agreement both in V-mag and B- V color distributions. A bimodal distribution in B- V at high galactic latitude seems to be represented by a halo and 'thick disk' dwarf in the blue and by a normal disk dwarf population in the red.