Results 21 to 30 of about 16,325 (263)

Realization of large energy proportion in the central lobe by coherent beam combination based on conformal projection system

Scientific Reports, 2017
In this paper, we experimentally validate a tiled-aperture conformal projection system with the largest array filling factor and element beam truncation factor to the best of our knowledge. The conformal projection system, which is made up of a hexagonal
Dong Zhi, Zhixin Zhang, Yanxing Ma, Xiaolin Wang, Zilun Chen, Wuming Wu, Pu Zhou, Lei Si   +7 more
doaj   +1 more source

Design Considerations for a Highly Segmented Mirror [PDF]

, 2003
Design issues for a 30-m highly segmented mirror are explored, with emphasis on parametric models of simple, inexpensive segments. A mirror with many small segments offers cost savings through quantity production and permits high-order active and ...
Padin, Stephen
core   +1 more source

Concept, modeling, and performance prediction of a low-cost, large deformable mirror [PDF]

, 2012
While it is attractive to integrate a deformable mirror (DM) for adaptive optics (AO) into the telescope itself rather than using relay optics within an instrument, the resulting large DM can be expensive, particularly for extremely large telescopes.
Andersen, Torben, Heimsten, Rikard, MacMynowski, Douglas G., Owner-Petersen, Mette   +3 more
core   +1 more source

Mode-Voltage Constrained Control for Adaptive Optics System

IEEE Photonics Journal
In the adaptive optics system of astronomical observation, the deformable mirror and the tip/tilt mirror are coupled during the correction process.
Ruitao Wang, Youming Guo, Nanfei Yan, Ying Yang, Lanqiang Zhang, Qiong Tu, Lingxiao Li, Changhui Rao   +7 more
doaj   +1 more source

Sensing and control of segmented mirrors with a pyramid wavefront sensor in the presence of spiders

, 2017
The segmentation of the telescope pupil (by spiders & the segmented M4) create areas of phase isolated by the width of the spiders on the wavefront sensor (WFS), breaking the spatial continuity of the wavefront.
Clarke, Fraser, Correia, Carlos, Dohlen, Kjetil, Fusco, Thierry, Hadi, Kacem El, Paufique, Jérome, Petit, Cyril, Quiros-Pacheco, Fernando, Sauvage, Jean-François, Schwartz, Noah, Thatte, Niranjan, Vernet, Joel   +11 more
core   +1 more source

The PRIMA fringe sensor unit [PDF]

, 2009
The Fringe Sensor Unit (FSU) is the central element of the Phase Referenced Imaging and Micro-arcsecond Astrometry (PRIMA) dual-feed facility and provides fringe sensing for all observation modes, comprising off-axis fringe tracking, phase referenced ...
Barry, Bean, Benedict, Bonnet, Colavita, Colavita, Colavita, Daigne, F. Delplancke, J. Sahlmann, Lane, Lane, Lane, Le Bouquin, Le Bouquin, Leinert, Lindegren, Linfield, Lévêque, M. Accardo, Monnier, Muterspaugh, Muterspaugh, Petrov, Pravdo, R. Abuter, S. Mottini, S. Ménardi, Shao, Shao, Shao, Tango, van Belle, Wyant   +33 more
core   +2 more sources

Piston Fuel Film Observations in an Optical Access GDI Engine [PDF]

SAE Technical Paper Series, 2001
<div class="htmlview paragraph">A gasoline direct injection fuel spray was observed using a fired, optical access, square cross-section single cylinder research engine and high-speed video imaging. Spray interaction with the piston is described qualitatively, and the results are compared with Computational Fluid Dynamics (CFD) simulation results ...
Rolf B. Karlsson, John B. Heywood
openaire   +1 more source

Hierarchical fringe tracking

, 2014
The limiting magnitude is a key issue for optical interferometry. Pairwise fringe trackers based on the integrated optics concepts used for example in GRAVITY seem limited to about K=10.5 with the 8m Unit Telescopes of the VLTI, and there is a general ...
Benkhaldoum, Zouhair, Boskri, Abdelkarim, Bresson, Yves, Elhalkouj, Thami, Folcher, Jean-Pierre, Lagarde, Stephane, Lazrek, Mohamed, Petrov, Romain G., Rakshit, Suvendu   +8 more
core   +1 more source

Stroke saturation on a MEMS deformable mirror for woofer-tweeter adaptive optics

, 2009
High-contrast imaging of extrasolar planet candidates around a main-sequence star has recently been realized from the ground using current adaptive optics (AO) systems. Advancing such observations will be a task for the Gemini Planet Imager, an upcoming "
Bruce Macintosh, Conan, Conan, Daren Dillon, Donald Gavel, Evans, Evans, Evans, Gavel, Gavel, Hardy, Hudgin, Kalas, Katie Morzinski, Lagrange, Lavigne, Macintosh, Malbet, Marois, Marois, Morzinski, Morzinski, Morzinski, Noll, Norton, Severson, Sommargren, Soummer, Stewart, Thomas, Vogel   +30 more
core   +1 more source

Atmospheric tomography with separate minimum variance laser and natural guide star mode control [PDF]

, 2009
This paper introduces a novel, computationally efficient, and practical atmospheric tomography wavefront control architecture with separate minimum variance laser and natural guide star mode estimation.
Ellerbroek, B. L., Gilles, L.
core   +1 more source