Brocken Specter and Glory

A Brocken specter forms when the shadow of the observer falls on a fog wall. The fog wall can be compared to a cinema screen on which the shadow is projected in multiple magnification. However, unlike the screen, fog does not have a smooth surface, so 3D images are created that change spookily through the swirling of the fog without the observer moving. Sometimes a colored, ring-shaped luminous phenomenon, the so-called glory, forms around the "head" of the Brocken specter. This is created by backscattering and subsequent diffraction of the sun's rays on the tiny fog droplets. The small round droplets deflect the light rays into a pattern of concentric circles. Since the glory forms around the counterpoint of the sun (in this case around the shadow of the mountain, building, airplane, observer, etc.), it can almost exclusively be observed from elevated points. The further the fog is away, the larger and more colorful the glory becomes, but the Brocken specter becomes increasingly smaller and more inconspicuous. However, another phenomenon often becomes visible: the fog bow. The first detailed description of Brocken specter and glory comes from the famous Spanish scientist and captain Ulloa, who crossed the Andes with the French scholar Bougner in 1735. The internationally used term "Ulloa's Ring" until the end of the 18th century was gradually replaced, not least by Goethe's "Theory of Colors," for which he also conducted optical-meteorological studies on the Brocken, making the term Brocken specter known in meteorological world literature. The Brocken impresses not only with extremely dense fog (visibility of only a few meters is not uncommon!) due to its eccentric location, but one likely encounters the Brocken specter there most frequently due to the average of over 300 foggy days a year.