Brocken Spectre & Glory, Brecon Beacons, Wales - OPOD

Last updated on September 16, 2023

Brocken Spectre & Glory: A Mystical Phenomenon in the Brecon Beacons, Wales

Have you ever witnessed a ghostly shadow surrounded by concentric rings of color, seemingly defying the laws of nature? If so, you might have encountered the captivating atmospheric phenomenon known as the Brocken Spectre and Glory. This mesmerizing spectacle can be observed in the western Brecon Beacons of Wales, where Colin Richards captured stunning images above the glacial lake of Llyn y Fan Fawr on December 13th, '14.

The Brocken Spectre, named after sightings by early climbers in the Harz Mountains of Germany, occurs when a person's shadow is cast upon mist or fog, creating an otherworldly silhouette. Each observer perceives their own unique spectre and glory. In the images captured by Colin Richards, the Brocken shadow visible is that of the photographer himself, not that of the subject being photographed. This eerie phenomenon is further enhanced by the outstretched arms of the photographer, appearing at an angle rather than horizontally.

When witnessing the Brocken Spectre, one might also notice a glorious phenomenon accompanying it. Known as a Glory, this wave-like effect adds an extra layer of mystique to the spectacle. The appearance of a Glory is caused by waves entering small mist droplets and deflection through approximately 180 degrees. This deflection occurs through multiple internal reflections within the droplets, creating a diffraction pattern that manifests as colored rings.

To fully understand the intricacies of a Glory, it is essential to comprehend the different wave paths involved. The primary wave path consists of a single internal reflection, which defies geometric optics. Additionally, there are wave paths with 10, 6, and 5 internal reflections that contribute to the formation of the Glory. The number of rings in the diffraction pattern varies depending on the wavelength of light and the size of the mist droplets. Glories with numerous rings are often observed when the mist droplets are almost monosized, such as in freshly formed fog.

The Brocken Spectre and Glory phenomenon is most commonly observed in misty environments, where the conditions are ideal for the formation of these captivating optical illusions. The Brecon Beacons in Wales, with their frequent mists, provide a picturesque backdrop for such sightings. As the photographer in Colin Richards' images casts a long, parallel shadow through the mist, the elongation of limbs and the interplay between shadow and light create an unearthly sight that is both mesmerizing and perplexing.

While the exact mechanisms behind the Brocken Spectre and Glory remain a subject of scientific study, one thing is certain: these atmospheric phenomena continue to fascinate and captivate both scientists and casual observers alike. The combination of mist, shadow, and diffraction creates a visual spectacle that challenges our understanding of light and optics. So, the next time you find yourself in the misty mountains of Wales or any other location prone to foggy conditions, keep an eye out for the ethereal beauty of the Brocken Spectre and Glory. You never know what wonders await you amidst the mist.

Brocken Spectre & Glory

Images by Colin Richards above the glacial lake of Llyn y Fan Fawr in the western Brecon Beacons, Wales on Saturday 13th December, ‘14.

A ghostly shadow looms below the ridge, its head surrounded by concentric rings of colour. We know that the Brocken Spectre is merely the shadow of the walker. But surely all is not right here? The walker has arms outstretched horizontal. The Brocken has its arms at an angle? Each observer sees their own personal spectre and glory. The Brocken shadow visible here is that of the photographer not that of the photographed. Images ©Colin Richards, shown with permission

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

The photographer looks straight down the shadow tube. Perspective renders 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.

A Glory.. ..is a wave rather than geometrical effect. 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 and part of the route involves 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

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