Heiligenschein is a bright spot of light around the shadow of the observer's head, cast on dewy grass land. The dew droplets on the grass act as lenses, focusing sunlight on the grass leaves, strongly illuminating them, and working again as a lens for the backscattered light. This effect is enhanced by the fact that in the antisolar point (the point opposite the sun, i.e. the shadow of one's head), no other shadows are visible, and thus the region looks much brighter because the light and dark details of the surface are integrated by the eye. Look for the Heiligenschein early in the morning, when the sun is low and thus your shadow long, and move yourself to let the shadow be cast on wet dewy grass. The effect is very common, so you should be likely to see it.
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