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Basden A.G.,Durham University | Chemla F.,University of Paris Descartes | Dipper N.,Durham University | Gendron E.,University of Paris Descartes | And 4 more authors.
Monthly Notices of the Royal Astronomical Society | Year: 2014

The use of laser guide stars in astronomical adaptive optics results in elongated Shack-Hartmann wavefront sensor image patterns. Image correlation techniques can be used to determine local wavefront slope by correlating each sub-aperture image with its expected elongated shape, or reference image. Here, we present a technique which allows the correlation reference images to be updated while the adaptive optics loop is closed. We show that this can be done without affecting the resulting point spread functions. On-sky demonstration is reported. We compare different techniques for obtaining the reference images, and investigate performance over a wide range of adaptive optics system parameters. We find that image correlation techniques perform better than the standard centre-of-gravity algorithm and are highly suited for use with open-loop multiple object adaptive optics systems. © 2014 The Author Published by Oxford University Press on behalf of the Royal Astronomical Society. Source

Basden A.G.,South Road | Evans C.J.,UKATC | Morris T.J.,South Road
Monthly Notices of the Royal Astronomical Society | Year: 2014

A multi-object spectrograph on the forthcoming European Extremely Large Telescope will be required to operate with good sky coverage. Many of the interesting deep cosmological fields were deliberately chosen to be free of bright foreground stars, and therefore are potentially challenging for adaptive optics (AO) systems. Here, we investigate multi-object AO performance using subfields chosen at random from within the Great Observatories Origins Deep Survey (GOODS)-S field, which is the worst case scenario for five deep fields used extensively in studies of high-redshift galaxies. Our AO system model is based on that of the proposed MOSAIC instrument but our findings are equally applicable to plans for multi-object spectroscopy on any of the planned Extremely Large Telescopes. Potential guide stars within these subfields are identified and used for simulations of AO correction. We achieve ensquared energies within 75 mas of between 25-35 per cent depending on the subfield, which is sufficient to probe sub-kpc scales in high-redshift galaxies. We also investigate the effect of detector readout noise on AO system performance, and consider cases where natural guide stars are used for both high-order and tip-tilt-only AO correction. We also consider how performance scales with ensquared energy box size. In summary, the expected AO performance is sufficient for a MOSAIC-like instrument, even within deep fields characterized by a lack of bright foreground stars. © 2014 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. Source

Lightfoot J.F.,UKATC | Juanola-Parramon R.,University College London | Savini G.,University College London
Hyperspectral Imaging and Sounding of the Environment, HISE 2015 | Year: 2015

FIInS is a Python software package developed to simulate the performance of a Double Fourier Interferometer in space. FIInS will 'observe' a model sky and incorporate the physics and errors expected from a real system. © OSA 2015. Source

Stobie B.,UKATC | Stewart M.,Sulaire Systems | Foster A.,Observatory science Ltd. | Delgadillo J.,The VERTEX
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2010

The VISTA Telescope1 is obtaining superb survey images. The M1 support system is essential to image quality and uses astatic pneumatic supports to balance the M1 against the varying effects of gravity and wind, with four axes being actively controlled via software and CANbus. The system also applies externally determined active optics force patterns. The mechanical, electronic, software and control design and as-built operation of the system are described, with the practical design points discussed. © 2010 SPIE. Source

Gigante J.V.,Institute of Astrophysics of Canarias | Rodriguez Ramos L.F.,Institute of Astrophysics of Canarias | Zins G.,Institute Of Planetologie Et Dastrophysique Of Grenoble | Schnetler H.,UKATC | And 4 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2014

HARMONI is an integral field spectrograph working at visible and near-infrared wavelengths over a range of spatial scales from ground layer corrected to fully diffraction-limited. The instrument has been chosen to be part of the first-light complement at the European Extremely Large Telescope (E-ELT). This paper describes the instrument control electronics to be developed at IAC. The large size of the HARMONI instrument, its cryogenic operation, and the fact that it must operate with enhanced reliability is a challenge from the point of view of the control electronics design. The present paper describes a design proposal based on the current instrument requirements and intended to be fully compliant with the ESO E-ELT standards, as well as with the European EMC and safety standards. The modularity of the design and the use of COTS standard hardware will benefit the project in several aspects, as reduced costs, shorter schedule by the use of commercially available components, and improved quality by the use of well proven solutions. © 2014 SPIE. Source

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