Bibcode
Masciadri, E.; Lascaux, F.; Fuensalida, J. J.; Lombardi, G.; Vázquez-Ramió, H.
Bibliographical reference
Monthly Notices of the Royal Astronomical Society, Volume 420, Issue 3, pp. 2399-2418.
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3
2012
Citations
11
Refereed citations
8
Description
Generalized SCIDAR (GS) measurements, which were taken at the Paranal
Observatory in 2007 November/December in the context of a site
qualification for the future European Extremely Large Telescope, are
recalibrated to overcome the bias induced on the ? profiles by an
incorrect normalization of the autocorrelation of the scintillation
maps, which has recently been identified in the GS technique. A complete
analysis of the GS-corrected measurements and the corrected errors is
performed statistically as well as on individual nights, and for each
time period during the nights. The relative errors of the ? profiles can
reach up to 60 per cent in some narrow temporal windows and some
vertical slabs, with the total seeing up to 12 per cent and the total
integrated turbulence J up to 21 per cent. However, the statistical
analysis shows that the absolute error of the median values of the total
seeing is 0.06 arcsec (relative error 5.6 per cent); for the boundary
seeing it is 0.05 arcsec (relative error 5.6 per cent) and for the
seeing in the free atmosphere it is 0.04 arcsec (relative error 9 per
cent). We find that, in spite of the fact that the relative error
increases with the height, the boundary and the free atmosphere seeing
contribute in an equivalent way to the error on the total seeing in
absolute terms. Moreover, we find that there are no correlations between
the relative errors and the value of the corresponding seeing. The
absolute error of the median value of the isoplanatic angle is 0.13
arcsec (relative error 6.9 per cent).