Lunar Halo, Jupiter, Contrail, and Shadow

May 21, 2003

Moonhalo-contrail copy

Provided by: Jean-Marie Maillard
Summary authors & editors: Jean-Marie Maillard; Jim Foster; Les Cowley

The remarkable photo above, taken in October of 2000, shows not only the full Moon, a lunar halo and the planet Jupiter, but the contrail of a jet aircraft and its shadow. In order for all of these things to be seen, the cirrus cloud layer responsible for the halo had to be thin enough to not obscure the Moon and Jupiter but sufficiently thick to show the shadow of the contrail cast upon it by the Moon. The aircraft and its contrail are of course above the cirrus layer. Since the halo is a 22 degree halo, the ice crystals in these cirrus clouds had to be poorly or even randomly oriented. This picture appeared previously in the "Bulletin of the Société Astronomique de Liège" (March, 2001) and in the French astronomical magazine "Ciel & Espace" (July, 2001).

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