Image quality and high contrast improvements on VLT/NACO

NACO is the famous and versatile diffraction limited NIR imager and spectrograph with which ESO celebrated 10 years of Adaptive Optics at the VLT. Since two years a substantial effort has been put in to understanding and fixing issues that directly affect the image quality and the high contrast performances of the instrument. Experiments to compensate the non-common-path aberrations and recover the highest possible Strehl ratios have been carried out successfully and a plan is hereafter described to perform such measurements regularly. The drift associated to pupil tracking since 2007 was fixed in October 2011. NACO is therefore even better suited for high contrast imaging and can be used with coronagraphic masks in the image plane. Some contrast measurements are shown and discussed. The work accomplished on NACO will serve as reference for the next generation instruments on the VLT, especially those working at the diffraction limit and making use of angular differential imaging (i.e. SPHERE, VISIR, possibly ERIS).Comment: 14 pages, 5 figures, SPIE 2012 Astronomical Instrumentation Proceedin

The E-ELT first light spectrograph HARMONI: capabilities and modes

Trabajo presentado en SPIE Astronomical Telescopes, celebrado en San Diego (California), del 26 de junio al 1 de julio de 2016HARMONI is the E-ELT's first light visible and near-infrared integral field spectrograph. It will provide four different spatial scales, ranging from coarse spaxels of 60 × 30 mas best suited for seeing limited observations, to 4 mas spaxels that Nyquist sample the diffraction limited point spread function of the E-ELT at near-infrared wavelengths. Each spaxel scale may be combined with eleven spectral settings, that provide a range of spectral resolving powers (R 3500, 7500 and 20000) and instantaneous wavelength coverage spanning the 0.5 - 2.4 ¿m wavelength range of the instrument. In autumn 2015, the HARMONI project started the Preliminary Design Phase, following signature of the contract to design, build, test and commission the instrument, signed between the European Southern Observatory and the UK Science and Technology Facilities Council. Crucially, the contract also includes the preliminary design of the HARMONI Laser Tomographic Adaptive Optics system. The instrument's technical specifications were finalized in the period leading up to contract signature. In this paper, we report on the first activity carried out during preliminary design, defining the baseline architecture for the system, and the trade-off studies leading up to the choice of baseline

Etude des galaxies lointaines et optiques adaptatives tomographiques pour ELTs

PARIS7-Bibliothèque centrale (751132105) / SudocSudocFranceF

Specifying an MOAO-fed integral field spectrograph for the E-ELT

International audienceWe present an end-to-end simulator for 3D spectroscopy, which can be used to specify MOAO-fed integral field spectrographs dedicated to ELTs. This simulator re-scales either local data or outputs of hydro-dynamical simulations to model distant galaxies. We present simulations of 3D observations in the H-band, for a rotating disk and a major merger at z=4, and a large range of stellar-mass. We use these simulations to explore the parameter space, focusing on the impact of the telescope diameter, total integration time, spectral resolution, and IFU pixel scale. The size of the telescope diameter has little influence on the spatial resolution of 3D observations but largely influences the achieved SNR. The choice of the IFU pixel scale is driven by the optimal "scale-coupling", i.e., the relation between the spatial resolution of 3D observations and the physical size of the features for which one needs to recover the kinematics using this IFU, and the SNR achieved with this spatial scale. To recover the dynamical state of distant emission line galaxies, one of the main goal of such future instruments, one only needs to recover their large-scale motions, which in turn requires only relatively coarse IFU pixel scales (50-75 mas) and moderate spectral resolution (R=5000)

Fourier filter LGS wavefront sensing for ELT size telescopes

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Focal-plane Cn2(h) profiling based on single-conjugate adaptive optics compensated images

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Exploration of convolutional neural networks to handle non-linearity estimation issues in pyramid wavefront sensors.

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Optimization of the pre-compensation of non-common path aberrations for AO systems

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Optimization of the pre-compensation of non-common path aberrations for AO systems

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