VASAO: visible all sky adaptive optics: a new adaptive optics concept for CFHT

International audienceVASAO is an ambitious project that explores new conceptual direction in the field of astronomical adaptive optics. In the era of 8 meter and larger telescopes, and their instrument costs and telescope time pressure, there is a natural niche for such ground-breaking conceptual development in the 4 meter class telescope. The aim of VASAO is to provide diffraction limited imaging in the visible with 100% sky coverage; the challenge (but potential rewards) arises from the simultaneity of these requirements. To this end, CFHT is conducting a feasibility study based on the polychromatic guide star concept (Foy et al., 1995 [4]) coupled with a high order curvature AO system, presented in this paper. A number of experiments have been started (or carried out) to study the challenges and limits of the techniques involved in an operational setting; these include the FlyEyes detector, and a polychromatic tip-tilt test on natural stars. Because such a project straddles such a fine line between facility instrument and experimental facility, careful thought has to be given to the balance between modes of operations and potential astrophysical targets

Patient-reported quality of life outcomes for children with serious congenital heart defects

Objective To compare patient-reported, health-related quality of life (QoL) for children with serious congenital heart defects (CHDs) and unaffected classmates and to investigate the demographic and clinical factors influencing QoL. Design Retrospective cohort study. Setting UK National Health Service. Patients UK-wide cohort of children with serious CHDs aged 10–14 years requiring cardiac intervention in the first year of life in one of 17 UK paediatric cardiac surgical centres operating during 1992–1995. A comparison group of classmates of similar age and sex was recruited. Main outcome measures Child self-report of healthrelated QoL scores (Pediatric Quality of Life Inventory, PedsQL) and parental report of schooling and social activities. Results Questionnaires were completed by 477 children with CHDs (56% boys; mean age 12.1 (SD 1.0) years) and 464 classmates (55%; 12.0 (SD 1.1) years). Children with CHDs rated QoL significantly lower than classmates (CHDs: median 78.3 (IQR 65.0–88.6); classmates: 88.0 (80.2–94.6)) and scored lower on physical (CHDs: 84.4; classmates: 93.8; difference 9.4 (7.8 to 10.9)) and psychosocial functioning subscales (CHDs: 76.7, classmates: 85.0; difference 8.3 (6.0 to 10.6)). Cardiac interventions, school absence, regular medications and non-cardiac comorbidities were independently associated with reduced QoL. Participation in sport positively influenced QoL and was associated with higher psychosocial functioning scores. Conclusions Children with serious CHDs experience lower QoL than unaffected classmates. This appears related to the burden of clinical intervention rather than underlying cardiac diagnosis. Participation in sports activities is positively associated with increased emotional well-being. Child self-report measures of QoL would be a valuable addition to clinical outcome audit in this age group.RLK was awarded an MRC Special Training Fellowship in Health of the Public and Health Services Research (reference G106/1083). TD was supported by an NIHR Academic Clinical Fellowship. This work was supported by a British Heart Foundation project grant (reference PG/02/065/13934). The Centre for Paediatric Epidemiology and Biostatistics benefits from funding support from the Medical Research Council in its capacity as the MRC Centre of Epidemiology for Child Health (reference G04005546). Great Ormond St Hospital for Children NHS Trust and the UCL Institute of Child Health receives a proportion of funding from the Department of Health’s NIHR Biomedical Research Centres schem

VASAO: visible all sky adaptive optics

International audienceBuilding on an extensive and successful experience in Adaptive Optics (AO) and on recent developments made in its funding nations, the Canada-France-Hawaii-Telescope Corporation (CFHT) is studying the VASAO concept: an integrated AO system that would allow diffraction limited imaging of the whole sky in the visible as well as in the infrared. At the core of VASAO, Pueo-Hou (the new Pueo) is built on Pueo, the current CFHT AO bonnette. Pueo will be refurbished and improved to be able to image the isoplanetic field at 700 nm with Strehl ratios of 30% or better, making possible imaging with a resolution of 50 milliarcseconds between 500 and 700nm, and at the telescope limit of diffraction above. The polychromatic tip-tilt laser guide star currently envisioned will be generated by a single 330nm mode-less laser, and the relative position of the 330nm and 589nm artificial stars created on the mesosphere by the 330nm excitation of the sodium layer will be monitored to provide the atmospheric tip-tilt along the line of sight, following the philosophy developed for the ELP-OA project. The feasibility study of VASAO will take most of 2006 in parallel with the development of a science case making the best possible use of the unique capabilities of the system, If the feasibility study is encouraging, VASAO development could start in 2007 for a full deployment on the sky by 2011-2012

Conceptual design study to determine optimal enclosure vent configuration for the Maunakea Spectroscopic Explorer (MSE)

The Maunakea Spectroscopic Explorer (MSE; formerly Next Generation Canada-France-Hawaii Telescope) is a dedicated, 10m aperture, wide-field, fiber-fed multi-object spectroscopic facility proposed as an upgrade to the existing Canada-France-Hawaii Telescope on the summit of Mauna Kea. The enclosure vent configuration design study is the last of three studies to examine the technical feasibility of the proposed MSE baseline concept. The enclosure vent configuration study compares the aero-thermal performance of three enclosure ventilation configurations based on the predicted dome thermal seeing and air flow attenuation over the enclosure aperture opening of a Calotte design derived from computational fluid dynamics simulations. In addition, functional and operation considerations such as access and servicing of the three ventilation configurations is discussed.Peer reviewed: YesNRC publication: Ye

FlyEyes: integrating CCID-35 into PUEO AO system at CFHT

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FlyEyes: A CCD-based Wavefront Sensor for PUEO, the CFHT Curvature AO System

International audienceAdaptive optics wavefront sensing imposes stringent requirements on detectors, due to the simultaneous need for extremely low read noise and high frame rates. Curvature wavefront sensing measurements are based on the normalized intensity of the signal in a given subaperture, and avalance photodiodes (APDs) have traditionally been used as detectors in curvature systems such as the Canada-France-Hawaii Telescope (CFHT) adaptive optics (AO) bonnette, called PUEO after the endemic Hawaiian owl. Passively quenched APDs are robust but have low QE (~40%), while actively quenched APDs can have much higher QE, but have been known to fail. Furthermore, curvature systems with large numbers of subapertures are now in operation, and the cost of individual APDs may become prohibitive for such systems. Thus, a CCD-based alternative appears very attractive, and development of a specific chip was initiated at ESO 10 years ago. In this article, we report on the performance of the FlyEyes camera, a project that was conceived to compare the performance of the backside-illuminated custom-designed CCD detector with an array of APDs, used in an operational and well-characterized curvature wavefront AO system. The on-sky performance is demonstrated to be unaffected on bright guide stars (i.e., negligible latency), and although the faint end suffers from the 2.5 e- read noise, the performance can be regained by lowering the frame rate on the wavefront sensor. In this article, we report on results that show that the CCD can be used to replace an array of expensive APDs. This would enable a cost-effective upgrade of PUEO to a higher-order system, as has been proposed at various occasions

FlyEyes: A CCD-based Wavefront Sensor for PUEO, the CFHT Curvature AO System

International audienceAdaptive optics wavefront sensing imposes stringent requirements on detectors, due to the simultaneous need for extremely low read noise and high frame rates. Curvature wavefront sensing measurements are based on the normalized intensity of the signal in a given subaperture, and avalance photodiodes (APDs) have traditionally been used as detectors in curvature systems such as the Canada-France-Hawaii Telescope (CFHT) adaptive optics (AO) bonnette, called PUEO after the endemic Hawaiian owl. Passively quenched APDs are robust but have low QE (~40%), while actively quenched APDs can have much higher QE, but have been known to fail. Furthermore, curvature systems with large numbers of subapertures are now in operation, and the cost of individual APDs may become prohibitive for such systems. Thus, a CCD-based alternative appears very attractive, and development of a specific chip was initiated at ESO 10 years ago. In this article, we report on the performance of the FlyEyes camera, a project that was conceived to compare the performance of the backside-illuminated custom-designed CCD detector with an array of APDs, used in an operational and well-characterized curvature wavefront AO system. The on-sky performance is demonstrated to be unaffected on bright guide stars (i.e., negligible latency), and although the faint end suffers from the 2.5 e- read noise, the performance can be regained by lowering the frame rate on the wavefront sensor. In this article, we report on results that show that the CCD can be used to replace an array of expensive APDs. This would enable a cost-effective upgrade of PUEO to a higher-order system, as has been proposed at various occasions

Maunakea spectroscopic explorer design development from feasibility concept to baseline design

International audienceThe Maunakea Spectroscopic Explorer is designed to be the largest non-ELT optical/NIR astronomical telescope, and will be a fully dedicated facility for multi-object spectroscopy over a broad range of spectral resolutions. The MSE design has progressed from feasibility concept into its current baseline design where the system configuration of main systems such as telescope, enclosure, summit facilities and instrument are fully defined. This paper will describe the engineering development of the main systems, and discuss the trade studies to determine the optimal telescope and multiplexing designs and how their findings are incorporated in the current baseline design