Astronomy and Astrophysics – Astrophysics
Scientific paper
2006-01-21
Astronomy and Astrophysics
Astrophysics
11 pages, 10 figures
Scientific paper
10.1051/0004-6361:20054143
Laser guide stars with adaptive optics allow astronomical image correction in the absence of a natural guide star. Single guide star systems with a star created in the earth's sodium layer can be used to correct the wavefront in the near infrared spectral regime for 8-m class telescopes. For possible future telescopes of larger sizes, or for correction at shorter wavelengths, the use of a single guide star is ultimately limited by focal anisoplanatism that arises from the finite height of the guide star. To overcome this limitation we propose to overlap coherently pulsed laser beams that are expanded over the full aperture of the telescope, traveling upwards along the same path which light from the astronomical object travels downwards. Imaging the scattered light from the resultant interference pattern with a camera gated to a certain height above the telescope, and using phase shifting interferometry we have found a method to retrieve the local wavefront gradients. By sensing the backscattered light from two different heights, one can fully remove the cone effect, which can otherwise be a serious handicap to the use of laser guide stars at shorter wavelengths or on larger telescopes. Using two laser beams multiconjugate correction is possible, resulting in larger corrected fields. With a proper choice of laser, wavefront correction could be expanded to the visible regime and, due to the lack of a cone effect, the method is applicable to any size of telescope. Finally the position of the laser spot could be imaged from the side of the main telescope against a bright background star to retrieve tip-tilt information, which would greatly improve the sky coverage of the system.
Davies Richard I.
Eisenhauer Frank
Genzel Reinhard
Ott Th.
Rabien Sebastian
No associations
LandOfFree
Atmospheric Turbulence Compensation with Laser Phase Shifting Interferometry does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Atmospheric Turbulence Compensation with Laser Phase Shifting Interferometry, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Atmospheric Turbulence Compensation with Laser Phase Shifting Interferometry will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-607260