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Credit: Adam Contos   
(Ball Aerospace)  
  
Explanation:
What do you get when you combine one of the world's most   
powerful telescopes   
with a powerful laser?    
  
An artificial star.    
  
Monitoring fluctuations   
in brightness of a genuine bright star can indicate how the   
Earth's atmosphere is changing,   
but many times no bright star exists in the direction where   
atmospheric information is needed.    
  
Therefore, astronomers have developed the ability to create an   
artificial star where they need it -- with a   
laser.   
  
Subsequent observations of the   
artificial laser guide star can reveal information so   
detailed about the blurring effects of the Earth's atmosphere   
that much of this blurring can be removed by rapidly flexing the mirror.   
  
Such adaptive optic techniques allow high-resolution   
ground-based observations of   
real stars,   
planets,   
nebulae,   
and the early universe.   
  
Above, a laser   
beam shoots out of the   
Keck II 10-meter telescope on Mauna  
Kea in   
Hawaii   
in 2002, creating an artificial star.  
  
  
  
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Based on Astronomy Picture
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Publications with keywords: telescope - laser
Publications with words: telescope - laser
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