Solstice Glory & Brocken Spectre

Imaged by Micheál Burke on Carrauntoohil, Ireland's highest peak. "I had bivvied up there the previous night for the Summer Solstice and awoke to see this beautiful sight." Zoomed view below.

                            Images ©Micheál Burke, shown with permission
 

A Glory..
    ..is a product of the wave nature of light. Waves enter small mist droplets and somehow emerge after deflection through 180 degrees or so.

The main wave path is one where they are internally reflected once. This is an impossible path for geometric optics through a water drop and part of the route is thought to involve waves along the drop surface.

Other wave paths with 10, 6 and 5 internal reflections contribute.

The glory diffraction pattern is wavelength dependent, hence the coloured rings. The best glories with many rings are from the almost monosized droplets of freshly formed fog.





The Brocken Spectre and glory are two separate effects. They are not always found together.

The Brocken Spectre is a simple shadow. The colourful ringed glory is altogether more complicated.

Both are directly opposite the sun. Both need direct sunlight shining through mist. Both best seen from a high vantage point but more earthly places work..

 

The observer looks straight down the shadow tube. Perspective makes the legs and arms greatly elongated. The shadows and rays can be thought of as a form of anticrepuscular rays with the observer inside the shadow.

The unexpected appearance in mist, the distortion and the occasional surrounding by a glory combine into an unearthly sight.

The name originates from sightings by early climbers of the Brocken in the Harz Mountains of Germany, a place of frequent mists.

Atmospheric
Optics
About - Submit Optics Picture of the Day Galleries Previous Next Today Subscribe to Features on RSS Feed
The Brocken shadow has extended legs and (faintly) arms with a diminutive head. It is a tube of shadow extending from the observer rather than a flat shadow as cast on a walll.

This glory has two obvious rings and traces of a third.

The shadow of Carrauntoohil falls on the slopes of Caher, Ireland's 3rd highest mountain. The glory is centred on the shadow of Carrauntoohil's summit and the position of where the camera's shadow would be if we could see it..

                  

Brocken Spectre
The observer casts a long, almost parallel, tube of shadow through mist lower down the mountain.