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Proceedings Paper

PIGS: first results on sky
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Paper Abstract

The next generation ground based telescopes deploy their full potential in terms of resolution only with Adaptive Optics (AO). A limiting factor for such systems is the sky coverage with natural guide stars. A way to overcome this problem is a artificial star, i.e. laser guide star (LGS) generated in the sodium layer of the mesosphere at an height of approximately 90km-100km. Sensing the wave front of such a LGS, whose photons are collected by a next generation ground based telescope up to 100m pupil diameter leads to new problems. They are related to the finite distance of the altitude where the artificial star forms with respect to the telescope entrance pupil. We present a new wave front sensing concept to overcome this problem and we show first results of an open loop experiment done on sky. Measurements have been carried out November 2003 with the Rayleigh laser of the University of Durham at the WHT in La Palma as a result of collaboration between MPIA and the AO group of the University of Durham. The geometry of the LGS created in 4km altitude with respect to the 4m aperture of the WHT scales by a factor 1:25 with a sodium LGS at 100km and a telescope with 100m entrance pupil diameter.

Paper Details

Date Published: 25 October 2004
PDF: 9 pages
Proc. SPIE 5490, Advancements in Adaptive Optics, (25 October 2004); doi: 10.1117/12.551722
Show Author Affiliations
Stephan Kellner, Max-Planck-Institut fur Astronomie (Germany)
Roberto Ragazzoni, Max-Planck-Institut fur Astronomie (Germany)
INAF, Osservatorio Astrofisico di Arcetri (Italy)
Wolfgang Gassler, Max-Planck-Institut fur Astronomie (Germany)
Emiliano Diolaiti, Univ. degli Studi di Padova (Italy)
Timothy J. Morris, Univ. of Durham (United Kingdom)
Christopher D. Saunter, Univ. of Durham (United Kingdom)
R. Meyers, Univ. of Durham (United Kingdom)
Jacopo Farinato, Max-Planck-Institut fur Astronomie (Germany)
INAF, Osservatorio Astrofisico di Arcetri (Italy)
Carmelo Arcidiacono, INAF, Osservatorio Astrofisico di Arcetri (Italy)
Adriano Ghedina, Telescopio Nazionale Galileo (Spain)

Published in SPIE Proceedings Vol. 5490:
Advancements in Adaptive Optics
Domenico Bonaccini Calia; Brent L. Ellerbroek; Roberto Ragazzoni, Editor(s)

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