27 September 1999 Experimental validation of tilt measurement technique with a laser beacon
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We have experimentally demonstrated for the first time a method for sensing wavefront tilt with a laser guide star (LGS). The tilt components of wavefronts were measured synchronously from the LGS using a telescope with 0.75 m effective aperture and from Polaris using a 1.5 m telescope. The Rayleigh guide star was formed at the altitude of 6 km and at a corresponding range of 10.5 km by projecting a focused beam at Polaris from the full aperture at the 1.5 m telescope. Both telescope mounts were unpowered and bottled down in place allowing us to substantially reduce the telescope vibration. The maximum value of the measured cross-correlation coefficient between the tilt for Polaris and the LGS is 0.71. The variations of the measured cross- correlation coefficient in the range from 0.22 to 0.71 are caused by turbulence at altitudes above 6 km, which was not sampled by the laser beacon, but affected the tilt for Polaris. It is also caused by the cone effect for turbulence below 6 km, residual mount jitter of the telescopes, and variations of the S/N. The experimental results support our concept of sensing atmospheric tilt by observing a LGS with an auxiliary telescope and indicate that this method is a possible solution for the tip-tilt problem.
© (1999) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Mikhail S. Belen'kii, Mikhail S. Belen'kii, Stephen J. Karis, Stephen J. Karis, James M. Brown, James M. Brown, Robert Q. Fugate, Robert Q. Fugate, } "Experimental validation of tilt measurement technique with a laser beacon", Proc. SPIE 3762, Adaptive Optics Systems and Technology, (27 September 1999); doi: 10.1117/12.363596; https://doi.org/10.1117/12.363596


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