Estimating Atmospheric Wind Speeds From Gemini Planet Imager AO Telemetry

The Earth's atmosphere is comprised of turbulent layers that result in speckled and blurry images from ground-based visible and infrared observations. Adaptive Optics (AO) systems are employed to measure the perturbed wavefront with a wavefront sensor (WFS) and correct for these distortions wit...

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Bibliographic Details
Published in:arXiv.org 2024-10
Main Authors: Du, Zhenxi, Perera, Saavidra, Levinstein, Daniel, Quinn Konopacky, Madurowicz, Alex, Macintosh, Bruce, Poyneer, Lisa, Wilson, Richard, Farley, Ollie
Format: Article
Language:English
Subjects:
Adaptive optics
Atmosphere
Atmospheric correction
Deformable mirrors
Deformation effects
Formability
High altitude
Infrared imagery
Parameters
Planet detection
Power spectral density
Telemetry
Wave front sensors
Wave fronts
Wind effects
Wind speed
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Summary:The Earth's atmosphere is comprised of turbulent layers that result in speckled and blurry images from ground-based visible and infrared observations. Adaptive Optics (AO) systems are employed to measure the perturbed wavefront with a wavefront sensor (WFS) and correct for these distortions with a deformable mirror. Therefore, understanding and characterising the atmosphere is crucial for the design and functionality of AO systems. One parameter for characterizing the atmosphere is the atmospheric coherence time, which is a function of the effective wind velocity of the atmosphere. This parameter dictates how fast the AO system needs to correct for the atmosphere. If not fast enough, phenomena such as the wind butterfly effect can occur, hindering high-contrast coronographic imaging. This effect is a result of fast, strong, high-altitude turbulent layers. This paper presents two methods for estimating the effective wind velocity, using pseudo-open loop WFS slopes. The first method uses a spatial-temporal covariance map and the second uses the power spectral density of the defocus term. We show both simulated results and preliminary results from the Gemini Planet Imager AO telemetry.
ISSN:2331-8422
DOI:10.48550/arxiv.2410.01193