When returning from our holidays this past year my daughter took the photo below. In it you can see the shadow of our plane upon a cloud surrounded by a radial rainbow. This optical phenomenon is called the “Brocken Spectre”. It occurs when the shadow of a person or an object is projected on mist or clouds. The shadow is often accompanied by a multicolored halo called a “Glory”, which is created when the light from the sun on the periphery of the shadow is diffracted by water droplets in the air.
The illusion is named after Brocken Mountain, which is the tallest mountain in the Harz Mountain Range in Germany. The foggy weather in this mountain range has led to many instances of locals witnessing and describing the Brocken Spectre throughout history, which has created a lore of fantastic tales associated with witches and devil worship. The first recorded description of the Brocken Spectre was made by the German theologician and natural scientist, Johann Silberschlag, in 1780.
The Brocken Spectre has been reported in many places throughout the world as well as by aviators since the early days of flying. It has been mentioned in works of literature by several authors including Charles Dickens and Lewis Carroll.
Image of the airplane Brocken Spectre belongs to the author and can only be used with permission.
Image of the person Brocken Spectre by Walter Baxter is used here under an Attribution-ShareAlike 2.0 Generic (CC BY-SA 2.0) license.