The Brocken spectre is an optical illusion in which the apparently greatly magnified shadow of an observer, when projected onto a surrounding mist by a back light such as the setting Sun, interferes with that observer’s depth perception. The shadow is perceived to be further away than it is in reality when seen against a background of features known to be far away, and hence much larger than it actually is.
The phenomenon takes its name from the highest peak in the Harz Mountains of north central Germany, the Brocken, where it was first reported. The term was coined in 1780 by Johann Silberschlag, a German pastor and natural scientist.
Other manifestations of the illusion include the Grey Man of Ben Macdui – Am Fear Liath Mòr in Scottish Gaelic – a creature once believed to haunt the summit and passes of Ben Macdui, the second highest peak in the British Isles after Ben Nevis.[a]Ben Macdui is in the Scottish Cairngorms.
|a||Ben Macdui is in the Scottish Cairngorms.|