Table 160 (continued) 

 HORIZONTAL VISIBILITY 



Table 160-C1. — Visual range of point sources of light 

 Function (log a h — log. E) 



473 



ixio- 



Threshold illuminance (flux-density), E, lumens km. -8 



2XlO" a 3XlO- a 4X10" 2 5X10" J 6XlO" s 7X10" 



8X10- S 9X10- 



Threshold illuminance (flux-density), E, lumens km. -2 



1X10"* 2X10" 8 3X10" 3 4X10- 8 5X10- 3 6X10" 8 7X10"' 8X10" 3 9X10" 



10* 16.118 15.425 15.019 14.732 14.509 14.326 14.172 



2X10* 16.811 16.118 15.713 15.425 15.202 15.019 14.865 



4X10* 17.504 16.811 16.406 16.118 15.895 15.713 15.558 



6X10* 17.910 17.217 16.811 16.524 16.300 16.118 15.964 



8X10* 18.198 17.504 17.099 16.811 16.588 16.406 16.252 



10 5 18.421 17.728 17.322 17.034 16.811 16.629 16.475 



5X10 5 20.030 19.337 18.932 18.644 18.421 18.238 18.084 



10 s 20.723 20.030 19.625 19.337 19.114 18.932 18.777 



5X10 9 22.333 21.640 21.234 20.946 20.723 20.541 20.387 



10 7 23.026 22.333 21.927 21.640 21.416 21.234 21.080 



5X10 7 24.635 23.942 23.537 23.249 23.026 22.844 22.689 



10 8 25.328 24.635 24.230 23.942 23.719 23.537 23.383 

 5X10 8 26.938 26.245 25.839 25.552 25.328 25.146 24.992 



10 e 27.631 26.938 26.532 26.245 26.022 25.839 25.685 



5X10" 29.240 28.547 28.142 27.854 27.631 27.449 27.295 



{continued) 



SMITHSONIAN METEOROLOGICAL TABLES 



