Solar seeing monitor MISOLFA: A new method for estimating atmospheric turbulence parameters
| Autor: | Abdanour Irbah, Luc Damé, Julien Borgnino, Djelloul Djafer, Philippe Keckhut |
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| Přispěvatelé: | STRATO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Unité de Recherche Appliquée en Energies Renouvelables (URAER), Ministère de l'Enseignement Supérieur et de la Recherche Scientifique [Algérie] (MESRS), HELIOS - LATMOS, CNRS (Centre National de la Recherche Scientifique), CNES (Centre National d’Etudes Spatiales), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS) |
| Jazyk: | angličtina |
| Rok vydání: | 2016 |
| Předmět: |
Physics
[PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph] Daytime Turbulence Astrophysics::Instrumentation and Methods for Astrophysics Mode (statistics) Data analysis Astronomy and Astrophysics Solar radius Atmospheric effects 01 natural sciences law.invention 010309 optics Telescope High angular resolution Space and Planetary Science Observatory law Optical transfer function 0103 physical sciences Angular resolution Site testing 010303 astronomy & astrophysics Instrumentation Remote sensing |
| Zdroj: | Astronomy and Astrophysics-A&A Astronomy and Astrophysics-A&A, EDP Sciences, 2016, 591, A150 (11p.). ⟨10.1051/0004-6361/201527914⟩ Astronomy and Astrophysics-A&A, 2016, 591, A150 (11p.). ⟨10.1051/0004-6361/201527914⟩ |
| ISSN: | 0004-6361 |
| DOI: | 10.1051/0004-6361/201527914⟩ |
| Popis: | International audience; Daily observation conditions are needed when observing the Sun at high angular resolution. MISOLFA is a daytime seeing monitor developed for this purpose that allows the estimation of the spatial and temporal parameters of atmospheric turbulence. This information is necessary, for instance, for astrometric measurements of the solar radius performed at Calern Observatory (France) with SODISM II, the ground-based version of the SODISM instrument of the PICARD mission.We present a new way to estimate the spatial parameters of atmospheric turbulence for daily observations. This method is less sensitive to vibrations and guiding defaults of the telescope since it uses short-exposure images. It is based on the comparison of the optical transfer function obtained from solar data and the theoretical values deduced from the Kolmogorov and Von Ka`rma`n models. This method, previously tested on simulated solar images, is applied to real data recorded at Calern Observatory in July 2013 with the MISOLFA monitor.First, we use data recorded in the pupil plane mode of MISOLFA and evaluate the turbulence characteristic times of angle- of-arrival fluctuations: between 5 and 16 milliseconds. Second, we use the focal plane mode of MISOLFA to simultaneously record solar images to obtain isoplanatic angles: ranging from 1 to 5 arcseconds (in agreement with previously published values). These images and our new method allow Fried’s parameter to be measured; it ranges from 0.5 cm to 4.7 cm with a mean value of 1.5 cm when Kolmogorov’s model is considered, and from less than 0.5 to 2.6 cm with a mean value of 1.3 cm for the Von Ka`rma`n model. Measurements of the spatial coherence outer scale parameter are also obtained when using the Von Karman model; it ranges from 0.25 to 13 meters with a mean value of 3.4 meters for the four days of observation that we analyzed. We found that its value can undergo large variations in only a few hours and that more data analysis is needed to better define its statistics. |
| Databáze: | OpenAIRE |
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