Halo and contrail shadow
Taken by Peg Zenko ( Tangent
Photos) near Chicago O'Hare Airport on an early morning
in March '04.
The delicate 22º halo is formed by ice crystals in a thin and
uniform layer of cirrus haze.
The aircraft and its contrail of water droplets and ice crystals
are high above the halo forming crystals and the sun is casting
a shadow of the contrail
downwards onto the cirrus layer.
©2004 Peg Zenko.