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Concept validation of a high dynamic range point-diffraction interferometer for wavefront sensing in adaptive optics (2022)
Journal Article
Dubost, N., Bharmal, N. A., Dubbeldam, M., & Myers, R. M. (2022). Concept validation of a high dynamic range point-diffraction interferometer for wavefront sensing in adaptive optics. Applied Optics, 61(14), 4160-4167. https://doi.org/10.1364/ao.439569

The direct detection and imaging of exoplanets requires the use of high-contrast adaptive optics (AO). In these systems quasi-static aberrations need to be highly corrected and calibrated. To achieve this, the pupil-modulated point-diffraction interf... Read More about Concept validation of a high dynamic range point-diffraction interferometer for wavefront sensing in adaptive optics.

Laboratory demonstration of an alternative laser guide stars wavefront sensing technique—projected pupil plane pattern (2019)
Journal Article
Yang, H., Bharmal, N., Myers, R., & Younger, E. (2019). Laboratory demonstration of an alternative laser guide stars wavefront sensing technique—projected pupil plane pattern. Journal of Astronomical Telescopes, Instruments, and Systems, 5(2), Article 029002. https://doi.org/10.1117/1.jatis.5.2.029002

Adaptive optics (AO) is widely used in optical/near-infrared telescopes to remove the effects of atmospheric distortion, and laser guide stars (LGSs) are commonly used to ease the requirement for a bright, natural reference source close to the scient... Read More about Laboratory demonstration of an alternative laser guide stars wavefront sensing technique—projected pupil plane pattern.

A many-core CPU prototype of an MCAO and LTAO RTC for ELT-scale instruments (2019)
Journal Article
Jenkins, D. R., Basden, A. G., & Myers, R. M. (2019). A many-core CPU prototype of an MCAO and LTAO RTC for ELT-scale instruments. Monthly Notices of the Royal Astronomical Society, 485(4), 5142-5152. https://doi.org/10.1093/mnras/stz638

We propose a many-core CPU architecture for Extremely Large Telescope (ELT) scale adaptive optics (AO) real-time control (RTC) for the multi-conjugate AO (MCAO) and laser-tomographic AO (LTAO) modes. MCAO and LTAO differ from the more conventional si... Read More about A many-core CPU prototype of an MCAO and LTAO RTC for ELT-scale instruments.

ELT-scale adaptive optics real-time control with the Intel Xeon Phi Many Integrated Core Architecture (2018)
Journal Article
Jenkins, D. R., Basden, A., & Myers, R. M. (2018). ELT-scale adaptive optics real-time control with the Intel Xeon Phi Many Integrated Core Architecture. Monthly Notices of the Royal Astronomical Society, 478(3), 3149-3158. https://doi.org/10.1093/mnras/sty1310

We propose a solution to the increased computational demands of Extremely Large Telescope (ELT) scale adaptive optics (AO) real-time control with the Intel Xeon Phi Knights Landing (KNL) Many Integrated Core (MIC) Architecture. The computational dema... Read More about ELT-scale adaptive optics real-time control with the Intel Xeon Phi Many Integrated Core Architecture.

Calibration of quasi-static aberrations in high-contrast astronomical adaptive optics with a pupil-modulated point-diffraction interferometer (2018)
Journal Article
Dubost, N., Bharmal, N., & Myers, R. M. (2018). Calibration of quasi-static aberrations in high-contrast astronomical adaptive optics with a pupil-modulated point-diffraction interferometer. Optics Express, 26(9), 11068-11083. https://doi.org/10.1364/oe.26.011068

The direct detection and imaging of exoplanets requires the use of high-contrast adaptive optics (AO). In these systems quasi-static aberrations need to be highly corrected and calibrated. In order to achieve this, a high-sensitivity wavefront sensor... Read More about Calibration of quasi-static aberrations in high-contrast astronomical adaptive optics with a pupil-modulated point-diffraction interferometer.

Projected Pupil Plane Pattern: an alternative LGS wavefront sensing technique (2018)
Journal Article
Yang, H., Bharmal, N. A., & Myers, R. M. (2018). Projected Pupil Plane Pattern: an alternative LGS wavefront sensing technique. Monthly Notices of the Royal Astronomical Society, 477(4), 4443-4453. https://doi.org/10.1093/mnras/sty926

We have analysed and simulated a novel alternative Laser Guide Star (LGS) configuration termed Projected Pupil Plane Pattern (PPPP), including wavefront sensing and the reconstruction method. A key advantage of this method is that a collimated beam i... Read More about Projected Pupil Plane Pattern: an alternative LGS wavefront sensing technique.

Centroid error compensation method for a star tracker under complex dynamic conditions (2017)
Journal Article
Tan, W., Qin, S., Myers, R., Morris, T., Jiang, G., Zhao, Y., …Dai, D. (2017). Centroid error compensation method for a star tracker under complex dynamic conditions. Optics Express, 25(26), 33559-33574. https://doi.org/10.1364/oe.25.033559

The traditional approach of a star tracker for reducing the dynamic error concentrates on a single frame of star images. Through correlating adjacent star images together with their angular relations sensed by a gyroscope unit (GU), the attitude-corr... Read More about Centroid error compensation method for a star tracker under complex dynamic conditions.

Wave-front error breakdown in laser guide star multi-object adaptive optics validated on-sky by CANARY (2017)
Journal Article
Martin, O., Gendron, É., Rousset, G., Gratadour, D., Vidal, F., Morris, T., …Henry, D. (2017). Wave-front error breakdown in laser guide star multi-object adaptive optics validated on-sky by CANARY. Astronomy & Astrophysics, 598, Article A37. https://doi.org/10.1051/0004-6361/201629271

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),... Read More about Wave-front error breakdown in laser guide star multi-object adaptive optics validated on-sky by CANARY.

On-sky demonstration of matched filters for wavefront measurements using ELT-scale elongated laser guide stars (2017)
Journal Article
Basden, A., Bardou, L., Bonaccini-Calia, D., Buey, T., Centrone, M., Chemla, F., …Vidal, F. (2017). On-sky demonstration of matched filters for wavefront measurements using ELT-scale elongated laser guide stars. Monthly Notices of the Royal Astronomical Society, 466(4), 5003-5010. https://doi.org/10.1093/mnras/stx062

The performance of adaptive optics systems is partially dependent on the algorithms used within the real-time control system to compute wavefront slope measurements. We demonstrate the use of a matched filter algorithm for the processing of elongated... Read More about On-sky demonstration of matched filters for wavefront measurements using ELT-scale elongated laser guide stars.

Preliminary on-sky results of the CANARY experiment with an ELT-elongated sodium LGS (2017)
Presentation / Conference Contribution
Bardou, L., Gendron, E., Rousset, G., Gratadour, D., Basden, A. G., Bonaccini, D., …Reyes Garcia-Talavera, M. (2017). Preliminary on-sky results of the CANARY experiment with an ELT-elongated sodium LGS. In Proceedings of the Adaptive Optics for Extremely Large Telescopes 5 (AO4ELT5) : Tenerife, Canary Islands, Spain, June 25-30, 2017. https://doi.org/10.26698/ao4elt5.0126

We present on-sky results of wavefront sensing on an elongated LGS. These results are derived from observations made with the multi-object AO demonstrator CANARY on the William Herschel Telescope (WHT) in La Palma. The laser guide star is produced us... Read More about Preliminary on-sky results of the CANARY experiment with an ELT-elongated sodium LGS.

Experience with wavefront sensor and deformable mirror interfaces for wide-field adaptive optics systems (2016)
Journal Article
Basden, A., Atkinson, D., Bharmal, N., Bitenc, U., Brangier, M., Buey, T., …Younger, E. (2016). Experience with wavefront sensor and deformable mirror interfaces for wide-field adaptive optics systems. Monthly Notices of the Royal Astronomical Society, 459(2), 1350-1359. https://doi.org/10.1093/mnras/stw730

Recent advances in adaptive optics (AO) have led to the implementation of wide field-of-view AO systems. A number of wide-field AO systems are also planned for the forthcoming Extremely Large Telescopes. Such systems have multiple wavefront sensors o... Read More about Experience with wavefront sensor and deformable mirror interfaces for wide-field adaptive optics systems.

A tomographic algorithm to determine tip-tilt information from laser guide stars (2016)
Journal Article
Reeves, A., Morris, T., Myers, R., Bharmal, N., & Osborn, J. (2016). A tomographic algorithm to determine tip-tilt information from laser guide stars. Monthly Notices of the Royal Astronomical Society, 459(1), 333-341. https://doi.org/10.1093/mnras/stw622

Laser Guide Stars (LGS) have greatly increased the sky-coverage of Adaptive Optics (AO) systems. Due to the up-link turbulence experienced by LGSs, a Natural Guide Star (NGS) is still required, preventing full sky-coverage. We present a method of obt... Read More about A tomographic algorithm to determine tip-tilt information from laser guide stars.

On-sky tests of the CuReD and HWR fast wavefront reconstruction algorithms with CANARY (2015)
Journal Article
Bitenc, U., Basden, A., Bharmal, N., Morris, T., Dipper, N., Gendron, E., …Myers, R. (2015). On-sky tests of the CuReD and HWR fast wavefront reconstruction algorithms with CANARY. Monthly Notices of the Royal Astronomical Society, 448(2), 1199-1205. https://doi.org/10.1093/mnras/stv003

CuReD (Cumulative Reconstructor with domain Decomposition) and HWR (Hierarchical Wavefront Reconstructor) are novel wavefront reconstruction algorithms for the Shack–Hartmann wavefront sensor, used in the single-conjugate adaptive optics. For a high-... Read More about On-sky tests of the CuReD and HWR fast wavefront reconstruction algorithms with CANARY.

Analysis of on-sky MOAO performance of CANARY using natural guide stars (2014)
Journal Article
Vidal, F., Gendron, E., Rousset, G., Morris, T., Basden, A., Myers, R., …Younger, E. (2014). Analysis of on-sky MOAO performance of CANARY using natural guide stars. Astronomy & Astrophysics, 569, Article A16. https://doi.org/10.1051/0004-6361/201322991

The first on-sky results obtained by CANARY, the multi-object adaptive optics (MOAO) demonstrator, are analysed. The data were recorded at the William Herschel Telescope, at the end of September 2010. We describe the command and calibrations algorith... Read More about Analysis of on-sky MOAO performance of CANARY using natural guide stars.

Open loop tomography with artificial neural networks on CANARY: on-sky results (2014)
Journal Article
Osborn, J., Guzman, D., De Cos Juez, F., Basden, A., Morris, T., Gendron, E., …Rousset, G. (2014). Open loop tomography with artificial neural networks on CANARY: on-sky results. Monthly Notices of the Royal Astronomical Society, 441(3), 2508-2514. https://doi.org/10.1093/mnras/stu758

We present recent results from the initial testing of an artificial neural network (ANN)-based tomographic reconstructor Complex Atmospheric Reconstructor based on Machine lEarNing (CARMEN) on CANARY, an adaptive optics demonstrator operated on the 4... Read More about Open loop tomography with artificial neural networks on CANARY: on-sky results.

Monte-Carlo simulation of ELT scale multi-object adaptive optics deformable mirror requirements and tolerances (2013)
Journal Article
Basden, A., Bharmal, N., Myers, R., Morris, S., & Morris, T. (2013). Monte-Carlo simulation of ELT scale multi-object adaptive optics deformable mirror requirements and tolerances. Monthly Notices of the Royal Astronomical Society, 435(2), 992-998. https://doi.org/10.1093/mnras/stt1302

Multi-object adaptive optics (MOAO) has been demonstrated by the CANARY instrument on the William Herschel Telescope. However, for proposed MOAO systems on the next-generation extremely large telescopes (ELTs), such as ELT Adaptive optics for GaLaxy... Read More about Monte-Carlo simulation of ELT scale multi-object adaptive optics deformable mirror requirements and tolerances.

The Durham adaptive optics real-time controller: capability and Extremely Large Telescope suitability (2012)
Journal Article
Basden, A., & Myers, R. (2012). The Durham adaptive optics real-time controller: capability and Extremely Large Telescope suitability. Monthly Notices of the Royal Astronomical Society, 424(2), 1483-1494. https://doi.org/10.1111/j.1365-2966.2012.21342.x

The Durham adaptive optics real-time controller is a generic, high-performance real-time control system for astronomical adaptive optics systems. It has recently had new features added as well as performance improvements, and here we give details of... Read More about The Durham adaptive optics real-time controller: capability and Extremely Large Telescope suitability.

Using artificial neural networks for open-loop tomography (2012)
Journal Article
Osborn, J., De Cos Juez, F. J., Guzman, D., Butterley, T., Myers, R., Guesalaga, A., & Laine, J. (2012). Using artificial neural networks for open-loop tomography. Optics Express, 20(3), 2420-2434. https://doi.org/10.1364/oe.20.002420

Modern adaptive optics (AO) systems for large telescopes require tomographic techniques to reconstruct the phase aberrations induced by the turbulent atmosphere along a line of sight to a target which is angularly separated from the guide sources tha... Read More about Using artificial neural networks for open-loop tomography.