$$
  {\rm in\ general\ \qquad } \theta  =  
            1.22 {\rm \ radians \ } \thinspace {{\lambda} \over {D}}
$$

$$
   {\rm in\ visible\ \quad } \theta  \sim  0.13 {\rm \ arcsec\ } 
            \thinspace\thinspace  {{1 {\rm \ meter}}\over{D}}  
$$


\bye
