Paranal Observatory has a set of astroclimate monitoring instruments; such as DIMM, MASS-DIMM and SLODAR which are delivering information about the sky quality in terms of; seeing, coherence time, high altitude wind speed (200mb) and C_n² profiles to support the observations. SPHERE instrument is an Extreme Adaptive Optics that uses a Shack-Hartmann wavefront sensor running at close loop frequency of 1.3KHz. The instrument saves close loop snapshot every minute and from the data saved the system retrieves the r0 and the cross wind speed. The wind speed is calculated using a cross-corrrelation based on the peak identification. The knowledge of t his parameter is essential to understand the performances of the AO system, and to optimize its control laws every minutes. The data from the astroclimatic system monitor will help to correlate the turbulence events with the transverse wind speed retrieved from SPHERE close loop data. The goal of this work is also to compare the different atmospheric monitors with the effective turbulence estimation from the focal plane itself (Differential Tip-Tilt Sensor).

Date Published: 4 August 2016
PDF: 12 pages
Proc. SPIE 9909, Adaptive Optics Systems V, 990937 (4 August 2016); doi: 10.1117/12.2233802

Published in SPIE Proceedings Vol. 9909:
Adaptive Optics Systems V
Enrico Marchetti; Laird M. Close; Jean-Pierre Véran, Editor(s)