Glory

Glory around the shadow of a plane. The position of the glory's centre 

shows that the observer was in front of the wings

A glory is an optical phenomenon resembling a halo that is caused by sunlight interacting with the tiny water droplets that compose mist or clouds. The glory consists of concentric, successively dimmer rings and is sometimes mistaken for a circular rainbow but the latter has a much larger diameter and is caused by different physical processes.

More: Wikipedia where I learn something new every day