Brocken spectre
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A Brocken spectre, also called Brocken bow or mountain spectre is the apparently enormously magnified shadow of an observer cast, when the Sun is low, upon the upper surfaces of clouds that are below the mountain upon which he stands. The phenomenon can appear on any misty mountainside (or even from an aircraft), but the frequent fogs and low-altitude accessibility of The Brocken, a peak in the Harz Mountains in Germany, have created a local legend. The spectre was observed and described by Johann Silberschlag in 1780, and has since been recorded often in literature about the region.
The "spectre" appears when the sun shines from behind a climber who is looking down from a ridge or peak into mist. The light projects the climber's shadow forward through the mist, often in an odd triangular shape due to perspective. The apparent magnification of size of the shadow is an optical illusion that occurs when the observer judges his shadow on relatively nearby clouds to be at the same distance as faraway land objects seen through gaps in the clouds. The shadow also falls on water droplets of varying distances from the eye, confusing depth perception. The ghost can appear to move (sometimes quite suddenly) because of the movement of the cloud layer.
The head of the figure is often surrounded by the glowing halo-like rings of a glory, rings of coloured light that appear directly opposite the sun when sunlight is reflected by a cloud of uniformly-sized water droplets.
