|Mists and mellow fruitfulness
Fogbow and heiligenschein by Jari Luomanen (Atmospheric Phenomena) on an Autumnal Finland morn.
©Jari Luomanen, shown with permission
|Rays are our own construct and an approximation but they are enough to describe the heiligenschein, the bright glow around the head's shadow when cast on dew wetted grass.
The dew drops focus the sun's light onto leaf surfaces where it is scattered backwards through the drop towards our eyes.
Wave diffraction is there too but its effects are not noticeable.
|Waves dominate fogbow formation. As in a rainbow they reflect off the drop's opposite face. But unlike a rainbow the drop is small (10-100 micron dia.) and the waves overlap and interfere to produce a broad and diffuse bow.|