Results 231 to 240 of about 39,077 (276)

Diffraction effects from giant segmented-mirror telescopes

Applied Optics, 2003
Ultrahigh contrast imaging with giant segmented-mirror telescopes will involve light levels of order 10(-6) times that of the central diffraction spike or less. At these levels it is important to quantify accurately various diffraction effects, including segmentation geometry, intersegment gaps, obscuration by the secondary mirror and its supports, and
Mitchell, Troy, Gary, Chanan
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ASM: scaled down active segmented mirror developed to simulate a segmented primary mirror

SPIE Proceedings, 2006
The Active Segmented Mirror is a key subsystem of the Active Phasing Experiment. The size of the ASM is 154 mm in diameter. It will be used to test new types of phasing sensors recently developed within the ELT design study supported by the European Union.
Christophe Dupuy, Christoph Frank, Frédéric Gonté, Constanza Araujo Hauck, Roland Brast, Regina Esteves, Matti Nylund, Babak Sedghi, Frédéric Derie   +8 more
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Segmented-mirror phased-array lasers

Applied Physics Letters, 1987
A scheme for phase-locked laser arrays in both one- and two-dimensional configurations is discussed. The scheme can be applied to any laser and its validity has been proved for the case of a pulsed neodimium laser.
DE SILVESTRI, SANDRO, LAPORTA, PAOLO, MAGNI, VITTORIO, SVELTO, ORAZIO   +3 more
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Deformable segmented mems mirror

The Journal of the Acoustical Society of America, 2005
A MEMS device having a deformable segmented mirror. The mirror includes a plurality of movable segments supported on a substrate using spring vertices, each vertex having a fixed plate and one or more springs. In a representative embodiment, three springs support each movable segment, where each spring connects the movable segment to a different spring
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Edge-Control on Mirror Segments

International Optical Design Conference and Optical Fabrication and Testing, 2010
We outline requirements for mirror segment edges for extremely large telescopes, and introduce the new CNC machine for process verification. We review a promising approach for edge-control using the Precessions process, and report progress.
David Walker, Anthony Beaucamp, Guoyu Yu, Hongyu Li   +3 more
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Segmented active / adaptive thin shell mirrors

Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation VI
Current ELTs use comparatively thick segmented mirrors with a support structure / warping structure of significant mass. In this publication we present a method to develop Segmented Thin Shell Mirrors that are intended to be supported by multiple actuators mounted on a backing structure.
Speet, B., Kamphues, F., Vreugd, J. de, Mourik, J., Hinz, P., Politopoulos, I., Navarro, R.   +6 more
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Segmented mirror adaptive optics system

Annual Meeting Optical Society of America, 1987
An adaptive optics system that utilizes a segmented mirror as the active component is described and discussed. The mirror is a 10-in. diam spherical mirror composed of 13 independently controllable segments of equal area. The system linearity and control laws are discussed assuming a modal wavefront expansion.
John D. Downie, Joseph W. Goodman, David Ennis   +2 more
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Segmented bimorph mirrors for adaptive optics: segment design and experiment

Applied Optics, 2014
We discuss the concept of lightweight segmented bimorph mirrors for adaptive optics. The segment consists of a monocrystal silicon substrate actuated by an array of in-plane piezoceramic (PZT) actuators with honeycomb electrodes. We focus on technological aspects of the segment design that are critical for space applications and describe a single ...
Bastaits, Renaud, Alaluf, David, Preumont, André, Horodinca, MIHAITA, Romanescu, Iulian, Burda, Ioan, Martic, Gregory, Rodrigues, Gonçalo   +7 more
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Segmented Mirrors For Atmospheric Compensation

SPIE Proceedings, 1989
An optical wavefront propagating through the atmosphere will be perturbed by local variations in the refractive index of the atmospheric gases. When accumulated over long optical path distances they will impart a spatial and temporally random distortion to the wavefront.
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Mirror antenna with hexagonal segmentation

International Symposium on Antennas and Propagation Society, Merging Technologies for the 90's, 1990
The antenna designed for radiometer applications on the planned NASA Earth Science Geostationary Platforms is described. This antenna consists of two parts: a regular parabolic dish 5 m in diameter which converts the radiation from feeds into a collimated beam, and a movable mirror that redirects the beam to a prescribed scan direction.
B. Houshmand, S.W. Lee, M. Zimmerman, R. Acosta   +3 more
openaire   +1 more source