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The Very Large Telescope (VLT) is a telescope operated by the European Southern Observatory on Cerro Paranal in the Atacama Desert of northern Chile. The VLT consists of four individual telescopes, each with a primary mirror 8.2 m across, which are generally used separately but can be used together to achieve very high angular resolution.〔(【引用サイトリンク】title=The Very Large Telescope )〕 The four separate optical telescopes are known as ''Antu'', ''Kueyen'', ''Melipal'' and ''Yepun'', which are all words for astronomical objects in the Mapuche language. The telescopes form an array which is complemented by four movable Auxiliary Telescopes (ATs) of 1.8 m aperture. The VLT operates at visible and infrared wavelengths. Each individual telescope can detect objects roughly four billion times fainter than can be detected with the naked eye, and when all the telescopes are combined, the facility can achieve an angular resolution of about 0.001 arc-second (This is equivalent to roughly 2 meters resolution at the distance of the Moon). In single telescope mode of operation angular resolution is about 0.05 arc-second.〔http://www.eso.org/public/about-eso/faq/faq-vlt-paranal/〕 The VLT is the most productive ground-based facility for astronomy, with only the Hubble Space Telescope generating more scientific papers among facilities operating at visible wavelengths. Among the pioneering observations carried out using the VLT are the first direct image of an exoplanet, the tracking of individual stars moving around the supermassive black hole at the centre of the Milky Way, and observations of the afterglow of the furthest known gamma-ray burst.〔(【引用サイトリンク】title=The Very Large Telescope — The World’s Most Advanced Visible-light Astronomical Observatory handout )〕 == General information == The VLT consists of an arrangement of four large (8.2 metre diameter) telescopes (called Unit Telescopes or UTs) with optical elements that can combine them into an astronomical interferometer (VLTI), which is used to resolve small objects. The interferometer also includes a set of four 1.8 meter diameter movable telescopes dedicated to interferometric observations. The first of the UTs started operating in May 1998 and was offered to the astronomical community on 1 April 1999. The other telescopes followed suit in 1999 and 2000, thus making the VLT fully operational. Four 1.8-metre Auxiliary Telescopes (ATs) have been added to the VLTI to make it available when the UTs are being used for other projects. These ATs were installed between 2004 and 2007. Today, all four Unit Telescopes and all four Auxiliary Telescopes are operational.〔 The VLT's 8.2-meter telescopes were originally designed to operate in three modes:〔(【引用サイトリンク】title=Science with the VLT in the ELT Era )〕 * as a set of four independent telescopes (this is the primary mode of operation). * as a single large coherent interferometric instrument (the VLT Interferometer or VLTI), for extra resolution. This mode is occasionally used, only for observations of relatively bright sources with small angular extent. * as a single large incoherent instrument, for extra light-gathering capacity. The instrumentation required to bring the light to a combined incoherent focus was not built. Recently, new instrumentation proposals have been put forward for making this observing mode available. Multiple telescopes are sometimes independently pointed at the same object, either to increase the total light-gathering power, or to provide simultaneous observations with complementary instruments. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Very Large Telescope」の詳細全文を読む スポンサード リンク
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