Abstract
The wavefront outer scale is an important parameter to use when evaluating the experimental performance of large aperture telescopes. Knowledge of three-dimensional atmospheric wavefront distortions is required for specifications of multiconjugate adaptive optics systems, which are essential for observations using Extremely Large Telescopes with a wider field of view. We aim to estimate the vertical distribution of the wavefront outer scale. We analyse the angular correlation of the fluctuations of the wavefront angle of arrival, deduced from image motion of the limb of the Moon. We use a simulated annealing algorithm to deduce the height dependence of the wavefront outer scale with given C 2 N profiles simultaneously measured with the scintillation detection and ranging (SCIDAR) instrument. We present results obtained during two campaigns of observation at the Mauna Kea Observatory (Hawaii) and the Observatoire de Haute Provence (France). Estimated profiles of the outer scale exhibit smaller values in the boundary layer than in the free atmosphere. Comparisons with measurements of the outer scale using the Generalized Seeing Monitor (GSM) are possible and give good agreement. We consider some implications for adaptive optics systems.
Highlights
Astronomical images produced by a ground-based telescope are severely degraded by wavefront atmospheric propagation
The performance and optimization of such systems are related to atmospheric conditions and notably to the amplitude of the wavefront outer scale, which gives an estimation of the spatial coherence and spatial correlation of the wavefront at large scales
We present a monitor of wavefront outer scale profiles (MOSP), which probes the correlations of the wavefront angle of arrival (AA) of the extent of the Moon’s limb
Summary
Astronomical images produced by a ground-based telescope are severely degraded by wavefront atmospheric propagation. The performance and optimization of such systems are related to atmospheric conditions and notably to the amplitude of the wavefront outer scale, which gives an estimation of the spatial coherence and spatial correlation of the wavefront at large scales. This is an important parameter that influences several topics in astronomy, such as diffraction-limited cores in uncorrected images, astrometric accuracy, the stroke of deformable mirrors and interferometer operations. Measurements of the outer scale have been confirmed by processing data obtained with existing high angular resolution
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
