Numerical simulations of a new approach for seeing measurement
| Autor: | Y. El Azhari, A. Habib, Zouhair Benkhaldoun |
|---|---|
| Rok vydání: | 2013 |
| Předmět: |
Physics
Diffraction Plane (geometry) business.industry Turbulence Fast Fourier transform Astrophysics::Instrumentation and Methods for Astrophysics Phase (waves) Astronomy and Astrophysics Computational physics Amplitude Optics Space and Planetary Science Astronomical seeing business Fresnel diffraction |
| Zdroj: | Monthly Notices of the Royal Astronomical Society. 434:742-747 |
| ISSN: | 1365-2966 0035-8711 |
| Popis: | Using a numerical simulation, a new approach to determine the wave structure function, and therefore the astronomical seeing, is presented and discussed. This method is based on the study of the diffraction pattern produced by a double slit at the focus plane of a telescope. The phase screens are simulated using a fast Fourier transform (FFT) based method and Kolmogorov’s law regarding atmospheric turbulence. From the scattered wave intensity, the wave structure function is calculated by taking into account both phase and amplitude fluctuations. This means that we can obtain a seeing value that is independent of the propagation distance between the turbulent layers and the ground level (Fresnel diffraction effect). Indeed, the seeing is related to the refractive-index structure constant (C 2 n ) inside the turbulent layers and thus should be independent of the aforementioned propagation distance. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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