Estimating Atmospheric Wind Speeds From Gemini Planet Imager Adaptive Optic 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 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.
Zhenxi Du, Saavidra Perera, Daniel Levinstein, Quinn Konopacky, Alex Madurowicz, Bruce Macintosh, Lisa Poyneer, Richard Wilson, Ollie Farley
Comments: 7 pages, 7 figures, submitted to SPIE Astronomical + Telescopes 2024
Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)
Cite as: arXiv:2410.01193 [astro-ph.IM] (or arXiv:2410.01193v1 [astro-ph.IM] for this version)
https://doi.org/10.48550/arXiv.2410.01193
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Journal reference: Proceedings Volume Adaptive Optics Systems IX, 130974E (2024)
Related DOI:
https://doi.org/10.1117/12.3020607
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Submission history
From: Zhenxi Du
[v1] Wed, 2 Oct 2024 02:57:41 UTC (1,660 KB)
https://arxiv.org/abs/2410.01193
Astrobiology, Astronomy,
