Fogbow, Glory and Brocken Spectre at the Golden Gate Bridge

March 07, 2008


Provided and copyright by: Mila Zinkova, Fogshadow
Summary authors & editors: Jim Foster, Mila Zinkova

The photo above showing a well defined glory, Brocken spectre and fogbow was taken at the Golden Gate Bridge in San Francisco, California. Like rainbows, fogbows result from refraction and reflection of sunlight by water droplets. In the case of the fogbow, however, the tiny droplets are less than about 0.5 mm in diameter. Diffraction processes (deflection of sunlight) are responsible for forming the glory and Brocken spectre seen at the apex of the fogbow. Note that they're all observed at the antisolar point, which is the point in the sky opposite of the Sun. The Brocken spectre is in essence the shadow of the observer (within the brightly colored glory) cast onto the mist.

There were many tourists at the bridge on this foggy mid-summer's day. The south tower was covered by fog, but the north tower was not. These tourists took picture after picture of the north tower cloaked in fog but seemed to completely miss the optics display just a slight turn from where they were standing, or perhaps they couldn't comprehend just what they were seeing. Photo taken on July 13, 2007.