Presentation 1 : None
Laser Guide Star : ELP-OA
Foy, R.et al.
We report the results of the feasibility study of the polychromatic
laser guide star (PLGS) concept to measure the tilt without any natural
guide star. Experiments on the sky at the LLNL (Ca) and at
CEA/Pierrelatte (France) to measure the return flux in particular at
330nm reasonably fit the CEA Optical Bloch equation model of the
population of the relevant enrgy levels of sodiu atoms in the
mesosphere. The accuracy of the measurement of the differential tilt
to derive the absolute tilt has been estimated from a horizontal
propagation experiment. A phase retrieval algorithm has been developed
to improve the measurement accuracy from the monochromatic components
of the polychromatic image. A pendular seismometer has been developed
to measure telescope vibrations. An end-to-end model has been
developed to evaluate the performances expected from a PLGS at different
telescopes. In conclusion, next steps of the "Étoile Laser
Polychromatique pour Optique" programme.
Adaptative" are described.