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Proceedings Paper

Assessing VLT-UT science image quality from active optics Shack-Hartmann spot patterns
Author(s): Julio Navarrete; Johan Kolb; Gianluca Lombardi; Lothar Noethe; Marc Sarazin
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Paper Abstract

A one year database has been gathered from the VLT active optics Shack-Hartmann (S-H) wavefront sensor images taken at each operating focus about every 30 seconds. The VLT telescope control software includes a dedicated code to extract the median full width at half maximum of the unvignetted S-H spots which is used for this study. This code applies a 1-D fit, assuming circular Hartmann spots, which allows to work only on foci equipped with atmospheric dispersion correction, or when the telescopes are observing close to zenith. The S-H image size measured inside the 30m enclosures is compared the outside seeing measured at 6m above ground by the VLT Astronomical Site Monitor (DIMM). A method for correcting DIMM measurements from surface layer turbulence contamination is proposed.

Paper Details

Date Published: 22 July 2014
PDF: 6 pages
Proc. SPIE 9145, Ground-based and Airborne Telescopes V, 91450C (22 July 2014); doi: 10.1117/12.2055736
Show Author Affiliations
Julio Navarrete, European Southern Observatory, LaSilla-Paranal Observatory (Chile)
Johan Kolb, European Southern Observatory (Germany)
Gianluca Lombardi, European Southern Observatory LaSilla-Paranal Observatory (Chile)
Lothar Noethe, European Southern Observatory (Germany)
Marc Sarazin, European Southern Observatory (Germany)


Published in SPIE Proceedings Vol. 9145:
Ground-based and Airborne Telescopes V
Larry M. Stepp; Roberto Gilmozzi; Helen J. Hall, Editor(s)

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