From: into@oblivion.nothing.com   
      
   laser  wrote in   
   news:c55b4320-23dc-43e7-ae95-4dc579121440@googlegroups.com:   
      
   > All the wavelength will be measured in air.   
   > Do you know the reason that there is an option to change wavelength from   
   > air to vacuum?   
      
   Because air has an index of refraction different than vacuum.   
      
   Brian   
   --   
   http://www.skywise711.com - Lasers, Seismology, Astronomy, Skepticism   
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