Dr. Fanny Chemla Profile

Dr. Fanny Chemla

Engineer at Observatoire de Paris à Meudon

SPIE Involvement:

Author

Publications (42)

PROCEEDINGS ARTICLE | July 30, 2018

The MICADO first light imager for the ELT: overview, operation, simulation

Proc. SPIE. 10702, Ground-based and Airborne Instrumentation for Astronomy VII

KEYWORDS: Adaptive optics, Distortion, Planets

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PROCEEDINGS ARTICLE | July 11, 2018

MOSAIC: the ELT multi-object spectrograph

Proc. SPIE. 10702, Ground-based and Airborne Instrumentation for Astronomy VII

KEYWORDS: Near infrared, Mirrors, Spectrographs, Visible radiation, Sensors, Adaptive optics, Microlens, Relays, Spatial resolution, Astronomical imaging

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PROCEEDINGS ARTICLE | July 11, 2018

Assembly, integration, test, and verification scenarios for the ELT MOSAIC instrument

Proc. SPIE. 10702, Ground-based and Airborne Instrumentation for Astronomy VII

KEYWORDS: Telescopes, Spectrographs, Calibration, Adaptive optics, Control systems, Integration, Mechanical engineering, Assembly equipment

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PROCEEDINGS ARTICLE | July 10, 2018

Product assurance for instrumental projects in research laboratory: galaxies, etoiles, physique, instrumentation (GEPI)

Proc. SPIE. 10705, Modeling, Systems Engineering, and Project Management for Astronomy VIII

KEYWORDS: Modeling, Safety, Aerospace engineering, Reliability, Analytical research, Document management, Galactic astronomy

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PROCEEDINGS ARTICLE | July 10, 2018

Closed loop operation with extremely elongated LGS spots in CANARY Phase D

Proc. SPIE. 10703, Adaptive Optics Systems VI

KEYWORDS: Telescopes, Optical filters, Stars, Cameras, Wavefront sensors, Adaptive optics, Control systems, Image filtering, Sodium, Laser guide stars

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CANARY is a wide-field AO on-sky test facility which has been operated annually on the 4.2m William Herschel Telescope since 2010. CANARY has the stated goal of testing and demonstrating AO technologies that are critical for ELT AO performance. It has seen four distinct phases where new AO technologies have been developed and demonstrated, including NGS MOAO in 2010 (phase A), Rayleigh LGS and NGS MOAO in 2012 and 2013 (phase B, with LGS commissioning in 2011), LTAO operation in 2014 and 2015, and finally operation with a single Sodium laser guide star launched far off axis in 2016 and 2017 (phase D). By launching this laser guide star 40m off axis, extremely elongated laser guide star spots are created in the CANARY LGS Shack-Hartmann wavefront sensor. Therefore, the 7×7 sub-apertures of CANARY can be used to test wavefront sensing performance of a sub-pupil of the ELT located furthest from the laser launch axis. We present an overview of CANARY in its phase D configuration. Depending on where in the sky the LGS is pointing, the projected baseline between the on-axis LGS wavefront sensor and the laser launch location, as seen by the wavefront sensor, will vary from about 20-40m, allowing us to artificially generate different degrees of elongation. Additionally, the well sampled CANARY sub-apertures have 30×30 pixels each and a 20 arcsecond field of view, using an OCAM2S EMCCD camera. This means that by shrinking sub-apertures, and optionally by binning pixels, we are able to investigate different pixel scales and fields of view for the ELT systems, thus determining the optimal design parameters. Here we discuss the closed loop tests that were performed to investigate the effect of spot truncation and extreme elongation. We include different correlation techniques, including standard FFT-based correlation, brute force correlation and correlation by difference squared. We also mention dynamic and automatic updates of the correlation reference images while the AO loop is engaged that have previously been reported. The matched filter algorithm is also mentioned, with a pointer to our prior on-sky investigations. We give our recommendation for the ELT wavefront sensing algorithm of choice, and our evidence based reasons for this recommendation, which may come as a surprise to some. Finally we also present the future experiments to be performed with CANARY, give details of the OPTICON funded programme which enables the hosting of AO experiments on CANARY, allowing the AO community to get involved.

PROCEEDINGS ARTICLE | July 10, 2018

Error breakdown of ELT-elongated LGS wavefront-sensing using CANARY on-sky measurements

Proc. SPIE. 10703, Adaptive Optics Systems VI

KEYWORDS: Telescopes, Stars, Wavefront sensors, Wavefronts, Adaptive optics, Data processing, Turbulence, Sodium, Laser guide stars

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PROCEEDINGS ARTICLE | July 10, 2018

Trade-offs in the visible spectrograph of the ELT instrument MOSAIC

Proc. SPIE. 10702, Ground-based and Airborne Instrumentation for Astronomy VII

KEYWORDS: Optical fibers, Spectrographs, Prisms, Visible radiation, Lenses, Cameras, Sensors, Adaptive optics, Collimators, Spectral resolution

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PROCEEDINGS ARTICLE | July 6, 2018

The ELT-MOS (MOSAIC): towards the construction phase

Proc. SPIE. 10702, Ground-based and Airborne Instrumentation for Astronomy VII

KEYWORDS: Near infrared, Telescopes, Spectrographs, Visible radiation, Astronomy, Sensors, Physics, Adaptive optics, Astronomical imaging, Galactic astronomy

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PROCEEDINGS ARTICLE | August 9, 2016

Developing an integrated concept for the E-ELT Multi-Object Spectrograph (MOSAIC): design issues and trade-offs

Proc. SPIE. 9908, Ground-based and Airborne Instrumentation for Astronomy VI

KEYWORDS: Near infrared, Telescopes, Spectrographs, Visible radiation, Cameras, Sensors, Adaptive optics, Adaptive optics, Laser guide stars, Astronomical imaging, Astronomical imaging, Electroluminescent displays

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PROCEEDINGS ARTICLE | July 27, 2016

Getting ready for the first on sky experiment using an ELT-scaled elongated sodium laser guide star