Thursday, November 27, 2014

LASER GUIDE STARS


 
Laser guide stars are an artificial star image created for use in astronomical adaptive optics imaging. The, by now classical approach, is to use a narrow-line laser emitting at a sodium resonance line wavelength to create a yellow artificial “star” in the ~ 95 km altitude sodium cloud around the Earth. When working with an Adaptive Optics system, this beacon provides a bright reference source to correct atmospheric turbulence in real time in fields devoid of bright enough natural stars; note however that a moderately bright natural star is still needed to correct global image motion in the field.

Source & reference:
http://www.eso.org/sci/facilities/develop/lgsf/overview.html
http://en.wikipedia.org/wiki/Laser_guide_star

Animation: ESO's Paranal Observatory projecting a laser into the night sky to create a sodium beacon guide star.

Credit: ESO/Gianluca Lombardi
http://metropolis79.wix.com/glphoto#!galleries/vstc1=astronomy

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