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Proceedings Paper

Subpupil estimation of the laser guide star tilt term
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Paper Abstract

We present a new technique aimed to obtain the downward tilt of a Laser Guide Star (LGS). The concept of this technique consists in averaging the LGS tilt signals as seen from many non-contiguous sub-pupils located on the telescope aperture. The sub-pupils tilt signals have two different contributions. One, common to all the various subpupils, is due to the upward beam propagation, the other, different on the various sub-pupils, is due to the downward beam propagation. These downward tilts have a correlation degree dependent on the sub-pupils array geometry and on the value of outer scale of turbulence. Summing up the sub-pupil signals allows to average out the tilt signal component due to the beacon downward propagation, so obtaining an estimation of the upward propagation laser beam tilt. We show here the achievable results in terms of the ratio between residual tip-tilt error variance obtained using this technique and the uncorrected tip-tilt variance. In particular the dependence from outer scale of turbulence and the use of multi-telescope systems are investigated.

Paper Details

Date Published: 17 October 1997
PDF: 9 pages
Proc. SPIE 3126, Adaptive Optics and Applications, (17 October 1997); doi: 10.1117/12.279056
Show Author Affiliations
Armando Riccardi, Osservatorio Astrofisico di Arcetri (Italy)
Simone Esposito, Osservatorio Astrofisico di Arcetri (Italy)
Roberto Ragazzoni, Osservatorio Astronomico di Padova (Italy)


Published in SPIE Proceedings Vol. 3126:
Adaptive Optics and Applications
Robert K. Tyson; Robert Q. Fugate, Editor(s)

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