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26 results on '"Ceppatelli, G."'

7. Glass mirrors by cold slumping to cover 100 m^2 of the MAGIC II Cherenkov telescope reflecting surface

Author

Pareschi, G., Giro, E., Banham, R., Basso, S., Bastieri, D., Canestrari, R., Ceppatelli, G., Citterio, O., Doro, Michele, Ghigo, M., Marioni, F., Mariotti, Mose', Salvati, M., Sanvito, F., Vernani, D., and Dietrich, Lemke

Subjects
Physics, One half, business.industry, Diamond, engineering.material, Cherenkov Telescope Array, law.invention, Telescope, Honeycomb structure, Optics, Coating, law, engineering, business, Cherenkov radiation, Slumping
Abstract

We report on the production and implementation of 100 square panels 1 m x 1 m, based on the innovative approach of cold slumping of thin glass sheets. The more than 100 segments will cover around one half of the 240 m-square reflecting surface of the MAGIC II, a clone of the atmospheric Cherenkov telescope MAGIC I (with a single-dish 17 m diameter mirror) which is already operating since late 2003 at La Palma. The MAGIC II telescope will be completed by the end of 2008 and will operate in stereoscopic mode with MAGIC I. While the central part of the of the reflector is composed of by diamond milled Aluminum of 1m2 area panels (following a design similar to that already used for MAGIC I), the outer coronas will be made of sandwiched glass segments. The glass panel production foresees the following steps: a) a thin glass sheet (1-2mm) is elastically deformed so as to retain the shape imparted by a master with convex profile - the radius of curvature is large, the sheet can be pressed against the master using vacuum suction -; b) on the deformed glass sheet a honeycomb structure that provides the needed rigidity is glued ; c) then a second glass sheet is glued on the top in order to obtain a sandwich; d) after on the concave side a reflecting coating (Aluminum) and a thin protective coating (Quartz) are deposited. The typical weight of each panel is about 12 kg and its resolution is better than 1 mrad at a level of diameter that contains the 90% of the energy reflected by the mirror; the areal cost of glass panels is ~2 k per 1m2. The technology based on cold slumping is a good candidate for the production of the primary mirrors of the telescopes forming the Cherenkov Telescope Array (CTA), the future large TeV observatory currently being studied in Europe. Details on the realization of MAGIC II new mirrors based on cold slumping glass will be presented.

Published
2008

9. THEMIS : Status and perspectives

Author

Ceppatelli, G., Briand, Carine, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Physique des plasmas, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris

Subjects
[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

International audience

Published
2003

11. THEMIS: instrumentation, results and perspectives

Author

Briand, Carine, Ceppatelli, G., Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Physique des plasmas, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris

Subjects
[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

International audience

Published
2002

17. Glass mirrors by cold slumping to cover 100 m2of the MAGIC II Cherenkov telescope reflecting surface

Author

Pareschi, G., primary, Giro, E., additional, Banham, R., additional, Basso, S., additional, Bastieri, D., additional, Canestrari, R., additional, Ceppatelli, G., additional, Citterio, O., additional, Doro, M., additional, Ghigo, M., additional, Marioni, F., additional, Mariotti, M., additional, Salvati, M., additional, Sanvito, F., additional, and Vernani, D., additional

Published
2008
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22. Optical remote sensing of atmospheric turbulence: a comparison with simultaneous thermal measurements

Author

Vernin, J., Barletti, R., Ceppatelli, G., Paternò, L., Righini, A., and Speroni, N.

Abstract

In this paper we describe a two-part experiment: measuring atmospheric turbulence both optically and thermally from 2 km up to the stratosphere. The consistency of the results shows that the optical technique may be a powerful tool for studying atmospheric turbulence from ground-based equipment.

Published
1979

26. Daytime r(0) evaluated from vertical microthermal measurements.

Author

Barletti R, Ceppatelli G, Paternò L, Righini A, and Speroni N

Abstract

The usefulness of parameter r(0) for describing the effect of atmospheric turbulence on wavefront distortion sensitive optical systems has been widely discussed. In this paper we present in situ daytime r(0) measurements (5500 A, Zenith propagation) obtained from balloon-borne microthermal radiosondes. We find that the parameter r(0) is log normal distributed at various levels aloft and that r(0) follows a power law in the 100-10,000-m range. Comparing our results with nighttime ground based observations we conclude that local turbulence prevails in determining image quality.

Published
1977
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