Glory (optical phenomenon)
From Wikipedia, the free encyclopediasaint's halo about the shadow of the observer's head. The effect is believed to happen due to classical wave tunneling, when light nearby the droplet tunnels through air inside the droplet and, in the case of glory, is emitted backwards due to resonance effects.
The angular size is much smaller than a rainbow, about 5° to 20°, depending on the size of the droplets. The glory can only be seen when the observer is directly between the sun and cloud of refracting water droplets. Hence, it is commonly observed whilst airborne, with the glory surrounding the airplane's shadow on clouds (this is often called The Glory of the Pilot). Glories can also be seen from mountains and tall buildings, when there are clouds or fog below the level of the observer. The phenomenon is related to the optical phenomenon anthelion.