Professor James Osborn's Outputs (74)

ELT-scale elongated LGS wavefront sensing: on-sky results (2021)
Journal Article
Bardou, L., Gendron, E., Rousset, G., Gratadour, D., Basden, A., Bonaccini Calia, D., Buey, T., Centrone, M., Chemla, F., Gach, J.-L., Geng, D., Hubert, Z., Laidlaw, D. J., Morris, T. J., Myers, R. M., Osborn, J., Reeves, A. P., Townson, M. J., & Vidal, F. (2021). ELT-scale elongated LGS wavefront sensing: on-sky results. Astronomy & Astrophysics, 649, Article A158. https://doi.org/10.1051/0004-6361/202038330

Context. Laser guide stars (LGS) allow adaptive optics (AO) systems to reach greater sky coverage, especially for AO systems correcting the atmospheric turbulence on large fields of view. However LGS suffer from limitations, among which is their appa... Read More about ELT-scale elongated LGS wavefront sensing: on-sky results.

Adaptive Optics pre-compensated laser uplink to LEO and GEO (2021)
Journal Article
Osborn, J., Townson, M., Farley, O., Reeves, A., & Mata Calvo, R. (2021). Adaptive Optics pre-compensated laser uplink to LEO and GEO. Optics Express, 29(4), 6113-6132. https://doi.org/10.1364/oe.413013

We present the results from a Monte Carlo computer simulation of adaptive optics (AO) pre-compensated laser uplink propagation through the Earth’s atmospheric turbulence from the ground to orbiting satellites. The simulation includes the so-called po... Read More about Adaptive Optics pre-compensated laser uplink to LEO and GEO.

Correction of finite spatial and temporal sampling effects in stereo-SCIDAR (2020)
Presentation / Conference Contribution
Butterley, T., Sarazin, M., Le Louarn, M., Osborn, J., & Farley, O. J. (2020, December). Correction of finite spatial and temporal sampling effects in stereo-SCIDAR. Presented at SPIE Astronomical Telescopes + Instrumentation 2020, Online

Stereo scintillation detection and ranging (S-SCIDAR) is a development of the well-established SCIDAR turbulence profiling technique. An S-SCIDAR instrument has been installed at the focus of one of the 1.8m Auxiliary Telescopes at Paranal observator... Read More about Correction of finite spatial and temporal sampling effects in stereo-SCIDAR.

On-sky results for adaptive optics control with data-driven models on low-order modes (2020)
Journal Article
Sinquin, B., Prengere, L., Kulcsár, C., Raynaud, H.-F., Gendron, E., Osborn, J., Basden, A., Conan, J.-M., Bharmal, N., Bardou, L., Staykov, L., Morris, T., Buey, T., Chemla, F., & Cohen, M. (2020). On-sky results for adaptive optics control with data-driven models on low-order modes. Monthly Notices of the Royal Astronomical Society, 498(3), 3228-3240. https://doi.org/10.1093/mnras/staa2562

Dedicated tip-tilt loops are commonly implemented on adaptive optics (AO) systems. In addition, a number of recent high-performance systems feature tip-tilt controllers which are more efficient than the integral action controller. In this context, Li... Read More about On-sky results for adaptive optics control with data-driven models on low-order modes.

Mesoscale modelling of optical turbulence in the atmosphere: the need for ultrahigh vertical grid resolution (2020)
Journal Article
Basu, S., Osborn, J., He, P., & DeMarco, A. (2020). Mesoscale modelling of optical turbulence in the atmosphere: the need for ultrahigh vertical grid resolution. Monthly Notices of the Royal Astronomical Society, 497(2), 2302-2308. https://doi.org/10.1093/mnras/staa2010

The high-fidelity modelling of optical turbulence is critical to the design and operation of a new class of emerging highly sophisticated astronomical telescopes and adaptive optics instrumentation. In this study, we perform retrospective simulations... Read More about Mesoscale modelling of optical turbulence in the atmosphere: the need for ultrahigh vertical grid resolution.

Wind-driven halo in high-contrast images (2020)
Journal Article
Cantalloube, F., Farley, O., Milli, J., Bharmal, N., Brandner, W., Correia, C., Dohlen, K., Henning, T., Osborn, J., Por, E., Suárez Valles, M., & Vigan, A. (2020). Wind-driven halo in high-contrast images. Astronomy & Astrophysics, 638, Article A98. https://doi.org/10.1051/0004-6361/201937397

Context. The wind-driven halo is a feature that is observed in images that were delivered by the latest generation of ground-based instruments that are equipped with an extreme adaptive optics system and a coronagraphic device, such as SPHERE at the... Read More about Wind-driven halo in high-contrast images.

Limitations imposed by optical turbulence profile structure and evolution on tomographic reconstruction for the ELT (2020)
Journal Article
Farley, O., Osborn, J., Morris, T., Fusco, T., Neichel, B., Correia, C., & Wilson, R. (2020). Limitations imposed by optical turbulence profile structure and evolution on tomographic reconstruction for the ELT. Monthly Notices of the Royal Astronomical Society, 494(2), 2773-2784. https://doi.org/10.1093/mnras/staa795

The performance of tomographic adaptive optics (AO) systems is intrinsically linked to the vertical profile of optical turbulence. First, a sufficient number of discrete turbulent layers must be reconstructed to model the true continuous turbulence p... Read More about Limitations imposed by optical turbulence profile structure and evolution on tomographic reconstruction for the ELT.

Characterization of the ground layer of turbulence at Paranal using a robotic SLODAR system (2019)
Journal Article
Butterley, T., Wilson, R., Sarazin, M., Dubbeldam, M., Osborn, J., & Clark, P. (2020). Characterization of the ground layer of turbulence at Paranal using a robotic SLODAR system. Monthly Notices of the Royal Astronomical Society, 492(1), 934-949. https://doi.org/10.1093/mnras/stz3498

We describe the implementation of a robotic SLODAR instrument at the Cerro Paranal observatory. The instrument measures the vertical profile of the optical atmospheric turbulence strength, in 8 resolution elements, to a maximum altitude ranging betwe... Read More about Characterization of the ground layer of turbulence at Paranal using a robotic SLODAR system.

Automated wind velocity profiling from adaptive optics telemetry (2019)
Journal Article
Laidlaw, D. J., Osborn, J., Morris, T. J., Basden, A. G., Gendron, E., Rousset, G., Townson, M. J., & Wilson, R. W. (2020). Automated wind velocity profiling from adaptive optics telemetry. Monthly Notices of the Royal Astronomical Society, 491(1), 1287-1294. https://doi.org/10.1093/mnras/stz3062

Ground-based adaptive optics (AO) systems can use temporal control techniques to greatly improve image resolution. A measure of wind velocity as a function of altitude is needed to minimize the temporal errors associated with these systems. Spatio-te... Read More about Automated wind velocity profiling from adaptive optics telemetry.

AOtools - a Python package for adaptive optics modelling and analysis (2019)
Journal Article
Townson, M., Farley, O., Orban de Xivry, G., Osborn, J., & Reeves, A. (2019). AOtools - a Python package for adaptive optics modelling and analysis. Optics Express, 27(22), 31316-31329. https://doi.org/10.1364/oe.27.031316

AOtools is a Python package that is open-source and aimed at providing tools for adaptive optics users and researchers. We present version 1.0, which contains tools for adaptive optics processing, including analysing data in the pupil plane, images a... Read More about AOtools - a Python package for adaptive optics modelling and analysis.

Atmospheric scintillation noise in ground-based exoplanet photometry (2019)
Journal Article
Föhring, D., Wilson, R., Osborn, J., & Dhillon, V. (2019). Atmospheric scintillation noise in ground-based exoplanet photometry. Monthly Notices of the Royal Astronomical Society, 489(4), 5098-5108. https://doi.org/10.1093/mnras/stz2444

Atmospheric scintillation caused by optical turbulence in the Earth’s atmosphere can be the dominant source of noise in ground-based photometric observations of bright targets, which is a particular concern for ground-based exoplanet transit photomet... Read More about Atmospheric scintillation noise in ground-based exoplanet photometry.

Experience with Artificial Neural Networks Applied in Multi-object Adaptive Optics (2019)
Journal Article
Suárez Gómez, S. L., González-Gutiérrez, C., Alonso, E. D., Santos, J. D., Rodríguez, M. L. S., Morris, T., Osborn, J., Basden, A., Bonavera, L., González, J. G.-N., & de Cos Juez, F. J. (2019). Experience with Artificial Neural Networks Applied in Multi-object Adaptive Optics. Publications of the Astronomical Society of the Pacific, 131(1004), Article 108012. https://doi.org/10.1088/1538-3873/ab1ebb

The use of artificial Intelligence techniques has become widespread in many fields of science, due to their ability to learn from real data and adjust to complex models with ease. These techniques have landed in the field of adaptive optics, and are... Read More about Experience with Artificial Neural Networks Applied in Multi-object Adaptive Optics.

Identifying optical turbulence profiles for realistic tomographic error in adaptive optics (2019)
Journal Article
Farley, O., Osborn, J., Morris, T., Fusco, T., Neichel, B., Correia, C., & Wilson, R. (2019). Identifying optical turbulence profiles for realistic tomographic error in adaptive optics. Monthly Notices of the Royal Astronomical Society, 488(1), 213-221. https://doi.org/10.1093/mnras/stz1669

For extremely large telescopes, adaptive optics will be required to correct the Earth’s turbulent atmosphere. The performance of tomographic adaptive optics is strongly dependent on the vertical distribution (profile) of this turbulence. An important... Read More about Identifying optical turbulence profiles for realistic tomographic error in adaptive optics.

Efficient implementation of pseudo open loop control for adaptive optics on Extremely Large Telescopes (2019)
Journal Article
Basden, A., Jenkins, D., Morris, T., Osborn, J., & Townson, M. (2019). Efficient implementation of pseudo open loop control for adaptive optics on Extremely Large Telescopes. Monthly Notices of the Royal Astronomical Society, 486(2), 1774-1780. https://doi.org/10.1093/mnras/stz918

Closed-loop adaptive optics systems which use minimum mean square error wavefront reconstruction require the computation of pseudo open loop wavefront slopes. These techniques incorporate a knowledge of atmospheric statistics which must therefore be... Read More about Efficient implementation of pseudo open loop control for adaptive optics on Extremely Large Telescopes.

Optimizing the accuracy and efficiency of optical turbulence profiling using adaptive optics telemetry for extremely large telescopes (2018)
Journal Article
Laidlaw, D. J., Osborn, J., Morris, T. J., Basden, A. G., Beltramo-Martin, O., Butterley, T., …Wilson, R. W. (2018). Optimizing the accuracy and efficiency of optical turbulence profiling using adaptive optics telemetry for extremely large telescopes. Monthly Notices of the Royal Astronomical Society, 483(4), 4341-4353. https://doi.org/10.1093/mnras/sty3285

Advanced adaptive optics (AO) instruments on ground-based telescopes require accurate knowledge of the atmospheric turbulence strength as a function of altitude. This information assists point spread function reconstruction, AO temporal control techn... Read More about Optimizing the accuracy and efficiency of optical turbulence profiling using adaptive optics telemetry for extremely large telescopes.

Representative optical turbulence profiles for ESO Paranal by hierarchical clustering (2018)
Journal Article
Farley, O., Osborn, J., Morris, T., Sarazin, M., Butterley, T., Townson, M., Jia, P., & Wilson, R. (2018). Representative optical turbulence profiles for ESO Paranal by hierarchical clustering. Monthly Notices of the Royal Astronomical Society, 481(3), 4030-4037. https://doi.org/10.1093/mnras/sty2536

Knowledge of the optical turbulence profile is important in adaptive optics (AO) systems, particularly tomographic AO systems such as those to be employed by the next generation of 40-m class extremely large telescopes. Site characterization and moni... Read More about Representative optical turbulence profiles for ESO Paranal by hierarchical clustering.

Modelling synthetic atmospheric turbulence profiles with temporal variation using Gaussian mixture model (2018)
Journal Article
Jia, P., Osborn, J., Kong, L., Laidlaw, D., Li, C., Farley, O., & Xue, G. (2018). Modelling synthetic atmospheric turbulence profiles with temporal variation using Gaussian mixture model. Monthly Notices of the Royal Astronomical Society, 480(2), 2466-2474. https://doi.org/10.1093/mnras/sty1951

The atmospheric turbulence profile plays a very important role for performance evaluation of wide-field adaptive optic systems. Since the atmospheric turbulence is evolving, the turbulence profile will change with time. To better model the temporal v... Read More about Modelling synthetic atmospheric turbulence profiles with temporal variation using Gaussian mixture model.

Atmospheric turbulence forecasting with a general circulation model for Cerro Paranal (2018)
Journal Article
Osborn, J., & Sarazin, M. (2018). Atmospheric turbulence forecasting with a general circulation model for Cerro Paranal. Monthly Notices of the Royal Astronomical Society, 480(1), 1278-1299. https://doi.org/10.1093/mnras/sty1898

In addition to astro-meteorological parameters, such as seeing, coherence time, and isoplanatic angle, the vertical profile of the Earth’s atmospheric turbulence strength and velocity is important for instrument design, performance validation and mon... Read More about Atmospheric turbulence forecasting with a general circulation model for Cerro Paranal.

Ground-layer adaptive-optics system modelling for the ChineseLarge Optical/Infrared Telescope (2018)
Journal Article
Peng, J., Basden, A., & Osborn, J. (2018). Ground-layer adaptive-optics system modelling for the ChineseLarge Optical/Infrared Telescope. Monthly Notices of the Royal Astronomical Society, 479(1), 829-843. https://doi.org/10.1093/mnras/sty1507

The Chinese Large Optical/Infrared Telescope is currently undergoing design studies. A ground-layer adaptive-optics system (GLAO) has been proposed, with a 14 -arcmin field of view (FOV) and moderate adaptive-optics correction using a deformable seco... Read More about Ground-layer adaptive-optics system modelling for the ChineseLarge Optical/Infrared Telescope.

Optical turbulence profiling with Stereo-SCIDAR for VLT and ELT (2018)
Journal Article
Osborn, J., Wilson, R., Sarazin, M., Butterley, T., Chacon, A., Derie, F., Farley, O., Haubois, X., Laidlaw, D., LeLouarn, M., Masciadri, E., Milli, J., Navarrete, J., & Townson, M. (2018). Optical turbulence profiling with Stereo-SCIDAR for VLT and ELT. Monthly Notices of the Royal Astronomical Society, 478(1), 825-834. https://doi.org/10.1093/mnras/sty1070

Knowledge of the Earth’s atmospheric optical turbulence is critical for astronomical instrumentation. Not only does it enable performance verification and optimisation of existing systems but it is required for the design of future instruments. As a... Read More about Optical turbulence profiling with Stereo-SCIDAR for VLT and ELT.