Heiligenschein

The halo is an optical phenomenon which occurs as a brightening around the shadow of the observer in appearance. If the observer moves, moves with the halo.

Formation

The halo is observed early in the morning on dewy meadows. The dewdrops focus lenses as the sunlight on the plants located in the background. Of the plant surface, the light is backscattered. Since the backscattered light again passes through the dew drops, built around the antisolar point, ie, the line connecting the sun, observer and shadow, the brightest area.

So that the light from the droplet can be focused, the dew drops must have a certain distance from the plant. Therefore, the halo is particularly visible on rough plants whose little hairs keep the drops into the plant at a distance.