CONTENTS

Annex 1    
 1     Atmospheric considerations         
 2     Absorption 
 3     Scattering   
        3.1     Rayleigh scattering 
        3.2     Mie scattering        
        3.3     Wavelength independent scattering 
 4     Refraction  
        4.1     Formula for the effective atmospheric refractive index         
        4.2     Apparent change in elevation angle 
 5     Turbulence 
        5.1     Measures of turbulence