TERMIUM Plus^®

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... the principal light-gathering surface of a reflective telescope.  2, fiche 1, Anglais, - primary%20mirror

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The primary mirror is located at the lower end of the telescope tube in a reflector and has its front surface coated with an extremely thin film of metal, such as aluminum. The back of the mirror is usually made of glass, although other materials have been used from time to time. Pyrex(trademark) was the principal glass of choice for many of the older large telescopes, but new technology has led to the development and widespread use of a number of glasses with very low coefficients of expansion.  3, fiche 1, Anglais, - primary%20mirror

Fiche 1,  Justifications,  Français

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On peut citer quelques formules optiques : le télescope de type Newton, qui utilise un miroir primaire concave sphérique ou parabolique et un miroir secondaire plan, c'est le montage le plus simple et le plus ancien, utilisé actuellement dans beaucoup de constructions d'amateurs. Il a été mis au point par Isaac Newton, le miroir plan est incliné à 45° et permet de renvoyer l'image focale à 90° de l'axe optique près de l'ouverture du tube.  2, fiche 1, Français, - miroir%20primaire

Fiche 1,  Justifications,  Espagnol

Fiche 2,  Justifications,  Anglais

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The Wide Field Corrector consists of a group of lenses that removes off-axis aberrations at the f/5 focus of the converted MMT [Multiple Mirror Telescope], allowing the telescope to offer excellent images over a very large field.  3, fiche 2, Anglais, - wide%20field%20corrector

Fiche 2,  Justifications,  Français

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« Le champ de vision de nos télescopes ne dépasse pas encore 1 degré, explique Ermanno Borra. Mais nous travaillons sur des correcteurs à grand champ qui nous permettront d'obtenir un champ de vision de 45 degrés, la moitié de celui d'un télescope conventionnel. » Les télescopes à miroirs liquides pourraient ainsi accéder à une région du ciel beaucoup plus grande.  3, fiche 2, Français, - correcteur%20%C3%A0%20grand%20champ

Fiche 2,  Justifications,  Espagnol

Fiche 3,  Justifications,  Anglais

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Orbiting Astronomical Observatory(OAO), series of four orbiting observatories launched between 1966 and 1972 by the National Aeronautics and Space Administration(NASA) to provide astronomical data in the ultraviolet and X-ray wavelengths filtered out by the earth's atmosphere. Only two of the four launches were successful, however. OAO-2, launched in 1978, which carried two large telescopes in addition to a cluster of four ultraviolet telescopes, four photoelectric telescopes, and a number of spectrometers and other devices, weighed 4, 200 lb(1, 900 kg) and was the heaviest satellite orbited to that time. Working primarily with ultraviolet radiation, it was able to photograph very young stars. OAO-3, which was also called Copernicus, was launched in 1972. Carrying what was at that time the largest telescope ever orbited and three smaller X-ray telescopes, OAO-3 was primarily used in the study of ultraviolet radiation from interstellar gas and dust and from stars near the edges of the Milky Way.  2, fiche 3, Anglais, - Orbiting%20Astronomical%20Observatory

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Fiche 3,  Justifications,  Espagnol