Using the ${C_{n}^{2}}$ and wind profiler method with wide-field laser-guide-stars adaptive optics to quantify the frozen-flow decay

Guesalaga, Andrés; Neichel, Benoît; Cortes, Angela; Béchet, Clementine; Guzmán, Dani

doi:10.1093/mnras/stu366

Cited by 35 publications

(51 citation statements)

References 26 publications

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“…Other sources have introduced a more sophisticated overlap factor (see e.g. Guesalaga et al 2014), but this is not necessary here, as we are not dealing with additional effects which can occur in real atmospheric images, such as shadows from mirror mounts or traces of laser guide stars. The approach to use a normalized cross-correlation in order to calculate an atmospheric shift is commonly used (Schöck & Spillar 2000;Wilson 2002;Guesalaga et al 2014).…”

Section: Wind Measurementmentioning

confidence: 99%

P-REx: The Piston Reconstruction Experiment for infrared interferometry

Widmann

Pott

Velasco

2017

Monthly Notices of the Royal Astronomical Society

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For sensitive infrared interferometry, it is crucial to control the differential piston evolution between the used telescopes. This is classically done by the use of a fringe tracker. In this work, we develop a new method to reconstruct the temporal piston variation from the atmosphere, by using real-time data from adaptive optics wavefront sensing: the Piston Reconstruction Experiment (P-REx). In order to understand the principle performance of the system in a realistic multilayer atmosphere it is first extensively tested in simulations. The gained insights are then used to apply P-REx to real data, in order to demonstrate the benefit of using P-REx as an auxiliary system in a real interferometer. All tests show positive results, which encourages further research and eventually a real implementation. Especially the tests on on-sky data showed that the atmosphere is, under decent observing conditions, sufficiently well structured and stable, in order to apply P-REx. It was possible to conveniently reconstruct the piston evolution in two-thirds of the datasets from good observing conditions (r 0 ∼ 30 cm). The main conclusion is that applying the piston reconstruction in a real system would reduce the piston variation from around 10 µm down to 1 to 2 µm over timescales of up to two seconds. This suggests an application for mid-infrared interferometry, for example for MATISSE at the VLTI or the LBTI. P-REx therefore provides the possibility to improve interferometric measurements without the need for more complex AO systems than already in regular use at 8m-class telescopes.

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Section: Wind Measurementmentioning

confidence: 99%

P-REx: The Piston Reconstruction Experiment for infrared interferometry

Widmann

Pott

Velasco

2017

Monthly Notices of the Royal Astronomical Society

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“…As GeMS is a closed-loop system, the next step is to construct the pseudo-open-loop slopes (POLSs) from on-sky data using the actuator voltages, the interaction matrix and the residual slopes (see Cortés et al 2012 andGuesalaga et al 2014 for a detailed explanation). After subtracting tip and tilt, these slopes are used to construct the auto-correlation of slopes using the normalization of overlapping subapertures described in Butterley et al (2006) and Wang, Schöck & Chanan (2008).…”

Section: Estimating the Integrated Lmentioning

confidence: 99%

“…In fact, after eliminating the effect of noise in the telemetry data and using fitting techniques, two or more functions with different outer scale provide a much better representation. The sharper component could be caused by dome seeing (Guesalaga et al 2014) or ground turbulence (Dali et al 2010). This means that the use of a single L 0 is not adequate to describe the spatial coherence of the atmosphere, since the response function can be the result of combining slopes from more than one layer, each with different outer scale values, i.e.…”

Section: Estimating the Integrated Lmentioning

confidence: 99%

Online estimation of the wavefront outer scale profile from adaptive optics telemetry

Guesalaga

Neichel

Correia

et al. 2016

Mon. Not. R. Astron. Soc.

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“…We implemented a system based on SLODAR method with ARGOS. The SLODAR technique must be modified to be applyed to AO system based on multiple laser guide stars and independent WFSs[4] [5]. The ARGOS's SLODAR is able estimate the turbulence strength in as many altitude bins as subapertures across the WFSs.…”

Section: Slodar Implementation With Argosmentioning

confidence: 99%