Moon and Mauna Kea Mountain Shadow

April 02, 2008

040208

Provided by: David Harrington, University of Hawaii, Institute for Astronomy
Summary author: David Harrington 

The photo above showing a magnificent view of the near full Moon rising next to the extended shadow of Mauna Kea was taken December 23, 2007, from the summit of Mauna Kea, Hawaii. The color has been stretched a little here. Mauna Kea is 13,796 ft tall (4,205 m) basaltic shield volcano. With the Sun low in the western sky, Mauna Kea’s shadow is on occasion projected against the distant atmosphere. For this effect to be observed, an abundance of aerosols must be present in the troposphere -- dust particles, for instance. The aerosols outside of the mountain shadow scatters sunlight. Inside of the shadow, this scattered sunlight is absent. All mountain shadows projected in this way appear triangular, even if they're flat-topped.