995 resultados para Astronomy.
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2nd ser. : v.9 (1831)
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2nd ser. : v.3 (1828)
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2nd ser. : v.4 (1828)
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When preparing an article on image restoration in astronomy, it is obvious that some topics have to be dropped to keep the work at reasonable length. We have decided to concentrate on image and noise models and on the algorithms to find the restoration. Topics like parameter estimation and stopping rules are also commented on. We start by describing the Bayesian paradigm and then proceed to study the noise and blur models used by the astronomical community. Then the prior models used to restore astronomical images are examined. We describe the algorithms used to find the restoration for the most common combinations of degradation and image models. Then we comment on important issues such as acceleration of algorithms, stopping rules, and parameter estimation. We also comment on the huge amount of information available to, and made available by, the astronomical community.
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Ground-based gamma-ray astronomy has had a major breakthrough with the impressive results obtained using systems of imaging atmospheric Cherenkov telescopes. Ground-based gamma-ray astronomy has a huge potential in astrophysics, particle physics and cosmology. CTA is an international initiative to build the next generation instrument, with a factor of 5-10 improvement in sensitivity in the 100 GeV-10 TeV range and the extension to energies well below 100 GeV and above 100 TeV. CTA will consist of two arrays (one in the north, one in the south) for full sky coverage and will be operated as open observatory. The design of CTA is based on currently available technology. This document reports on the status and presents the major design concepts of CTA.
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Ground-based gamma-ray astronomy has had a major breakthrough with the impressive results obtained using systems of imaging atmospheric Cherenkov telescopes. Ground-based gamma-ray astronomy has a huge potential in astrophysics, particle physics and cosmology. CTA is an international initiative to build the next generation instrument, with a factor of 5-10 improvement in sensitivity in the 100 GeV-10 TeV range and the extension to energies well below 100 GeV and above 100 TeV. CTA will consist of two arrays (one in the north, one in the south) for full sky coverage and will be operated as open observatory. The design of CTA is based on currently available technology. This document reports on the status and presents the major design concepts of CTA.
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Ground-based gamma-ray astronomy has had a major breakthrough with the impressive results obtained using systems of imaging atmospheric Cherenkov telescopes. Ground-based gamma-ray astronomy has a huge potential in astrophysics, particle physics and cosmology. CTA is an international initiative to build the next generation instrument, with a factor of 5-10 improvement in sensitivity in the 100 GeV-10 TeV range and the extension to energies well below 100 GeV and above 100 TeV. CTA will consist of two arrays (one in the north, one in the south) for full sky coverage and will be operated as open observatory. The design of CTA is based on currently available technology. This document reports on the status and presents the major design concepts of CTA.
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Digital reproduction, The National Library of Finland, Centre for Preservation and Digitisation, Mikkeli
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Statistical analyses of measurements that can be described by statistical models are of essence in astronomy and in scientific inquiry in general. The sensitivity of such analyses, modelling approaches, and the consequent predictions, is sometimes highly dependent on the exact techniques applied, and improvements therein can result in significantly better understanding of the observed system of interest. Particularly, optimising the sensitivity of statistical techniques in detecting the faint signatures of low-mass planets orbiting the nearby stars is, together with improvements in instrumentation, essential in estimating the properties of the population of such planets, and in the race to detect Earth-analogs, i.e. planets that could support liquid water and, perhaps, life on their surfaces. We review the developments in Bayesian statistical techniques applicable to detections planets orbiting nearby stars and astronomical data analysis problems in general. We also discuss these techniques and demonstrate their usefulness by using various examples and detailed descriptions of the respective mathematics involved. We demonstrate the practical aspects of Bayesian statistical techniques by describing several algorithms and numerical techniques, as well as theoretical constructions, in the estimation of model parameters and in hypothesis testing. We also apply these algorithms to Doppler measurements of nearby stars to show how they can be used in practice to obtain as much information from the noisy data as possible. Bayesian statistical techniques are powerful tools in analysing and interpreting noisy data and should be preferred in practice whenever computational limitations are not too restrictive.
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Traduction d'Alexander Wylie (1815-1887), rédigée par Li Shan lan. Préface anglaise de Wylie, écrite à Shang hai (décembre 1859), suivie d'une note relative à la publication des Chinois 4885 et 4886. Vocabulaire de termes techniques. Préface Chinoise de Wylie (1859). Texte et figures ; les planches hors texte sont tirées sur papier européen. Imprimé en caractères mobiles, dans la maison Mo hai.18 livres.
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Logo for the school of Physics and Astronomy in Inkscape SVG, PDF and high-resolution PNG format
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La Astronomía estudia el universo por medio de telescopios y sondas espaciales. Se compone de diferentes disciplinas como la astrobiología, la cosmología y la astrofísica. Aquí se explica cómo ayuda a desentrañar los secretos del espacio y debatir sobre cómo empezó el universo, cuál será su final y la posibilidad de vida en otros planetas.
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Examina la historia de esta ciencia considerada la más antigua de todas por el interés que desde la antigüedad ha suscitado en los hombres el conocimiento de los complejos movimientos de los objetos celestiales.También, se repasan los orígenes del universo con la violenta explosión ocurrida hace billones de años, llamada Big Bang. Se estudia el sistema solar, formado de planetas, lunas e innumerables cuerpos más pequeños como asteroides y cometas. Se completa con una observación de las estrellas y galaxias en el cielo de la noche, con cartas estelares y perfiles de constelaciones y, por último, se añade una guía con la posición mes a mes de las constelaciones septentrionales y australes.