Experimental study of an optimised Pyramid wave-front sensor for Extremely Large Telescopes

2016 ◽  
Author(s):  
Charlotte Z. Bond ◽  
Kacem El Hadi ◽  
Jean-François Sauvage ◽  
Carlos Correia ◽  
Olivier Fauvarque ◽  
...  
Keyword(s):  
Experimental Study ◽  
Wave Front ◽  
Large Telescopes

An experimental study on reflector wave-front error correction using PZT actuators

2016 ◽  
Author(s):  
Lan Lan ◽  
Shuidong Jiang ◽  
Yang Zhou ◽  
Houfei Fang ◽  
Zhigang Wu ◽  
...  
Keyword(s):  
Experimental Study ◽  
Error Correction ◽  
Wave Front

Experimental study of the influence of wave-front aberration on holographic data storage

2010 ◽  
Author(s):  
Naruki Yoshida ◽  
Kensuke Akieda ◽  
Akihito Nakajima ◽  
Yosuke Takahata ◽  
Manabu Yamamoto
Keyword(s):  
Experimental Study ◽  
Wave Front ◽  
Data Storage ◽  
Holographic Data Storage

scholarly journals Wave-front error breakdown in laser guide star multi-object adaptive optics validated on-sky by Canary

2017 ◽  
Vol 598 ◽  
pp. A37 ◽  
Author(s):  
O. A. Martin ◽  
É. Gendron ◽  
G. Rousset ◽  
D. Gratadour ◽  
F. Vidal ◽  
...  
Keyword(s):  
Wave Front ◽  
Adaptive Optics ◽  
Open Loop ◽  
System Modelling ◽  
Large Set ◽  
Vertical Error ◽  
Guide Star ◽  
Laser Guide ◽  
Large Telescopes ◽  
William Herschel

Context. Canary is the multi-object adaptive optics (MOAO) on-sky pathfinder developed in the perspective of multi-object spectrograph on extremely large telescopes (ELTs). In 2013, Canary was operated on-sky at the William Herschel telescope (WHT), using three off-axis natural guide stars (NGS) and four off-axis Rayleigh laser guide stars (LGS), in open-loop, with the on-axis compensated turbulence observed with a H-band imaging camera and a Truth wave-front sensor (TS) for diagnostic purposes. Aims. Our purpose is to establish a reliable and accurate wave-front error breakdown for LGS MOAO. This will enable a comprehensive analysis of Canary on-sky results and provide tools for validating simulations of MOAO systems for ELTs. Methods. To evaluate the MOAO performance, we compared the Canary on-sky results running in MOAO, in single conjugated adaptive optics (SCAO) and in ground layer adaptive optics (GLAO) modes, over a large set of data acquired in 2013. We provide a statistical study of the seeing. We also evaluated the wave-front error breakdown from both analytic computations, one based on a MOAO system modelling and the other on the measurements from the Canary TS. We have focussed especially on the tomographic error and we detail its vertical error decomposition. Results. We show that Canary obtained 30.1%, 21.4% and 17.1% H-band Strehl ratios in SCAO, MOAO and GLAO respectively, for median seeing conditions with 0.66′′ of total seeing including 0.59′′ at the ground. Moreover, we get 99% of correlation over 4500 samples, for any AO modes, between two analytic computations of residual phase variance. Based on these variances, we obtain a reasonable Strehl-ratio (SR) estimation when compared to the measured IR image SR. We evaluate the gain in compensation for the altitude turbulence brought by MOAO when compared to GLAO.

Experimental study on the restoration from a tilt-azimuth series for improvement in resolution

1995 ◽  
Vol 53 ◽  
pp. 636-637
Author(s):  
Norio Baba ◽  
Norihiko Ichise ◽  
Syunya Watanabe
Keyword(s):  
Experimental Study ◽  
Spherical Aberration ◽  
Incident Beam ◽  
Optical Parameters ◽  
Beam Tilting ◽  
Illumination Method ◽  
Restoration Method ◽  
Illumination Mode

The tilted beam illumination method is used to improve the resolution comparing with the axial illumination mode. Using this advantage, a restoration method of several tilted beam images covering the full azimuthal range was proposed by Saxton, and experimentally examined. To make this technique more reliable it seems that some practical problems still remain. In this report the restoration was attempted and the problems were considered. In our study, four problems were pointed out for the experiment of the restoration. (1) Accurate beam tilt adjustment to fit the incident beam to the coma-free axis for the symmetrical beam tilting over the full azimuthal range. (2) Accurate measurements of the optical parameters which are necessary to design the restoration filter. Even if the spherical aberration coefficient Cs is known with accuracy and the axial astigmatism is sufficiently compensated, at least the defocus value must be measured. (3) Accurate alignment of the tilt-azimuth series images.

An Experimental Study of Some Properties of Stuttered Words

1962 ◽  
Vol 5 (4) ◽  
pp. 387-394 ◽  
Author(s):  
Bruce Quarrington ◽  
Jerome Conway ◽  
Nathan Siegel
Keyword(s):  
Experimental Study
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