Paraachute Optics, Glory and fogbow

Last updated on September 16, 2023

Parachute Optics: Unveiling the Wonders of Glory and Fogbow

Have you ever marveled at the breathtaking beauty of the sky while parachuting? The world above offers more than just an adrenaline rush; it presents an opportunity to witness captivating atmospheric optics phenomena. One such spectacle is the interplay between parachutes and the surrounding clouds, giving rise to vibrant glories and ethereal fogbows. In this article, we will delve into the intricacies of parachute optics, exploring the science behind glories, fogbows, and their enchanting visual displays.

The Enigmatic Glory

Glories are captivating optical phenomena that manifest as colorful rings encircling the shadow of an object, such as a parachutist, when illuminated by sunlight. These phenomena are always positioned directly opposite the sun, precisely where the shadow of your camera or eye falls. Imagine witnessing the magnificent sight of a parachutist's shadow adorned by a resplendent ring of colors against a backdrop of thin clouds. It's truly a sight to behold!

Within the glory, you may observe a captivating phenomenon known as the "Brocken Spectre" shadow. This shadow appears as a magnified silhouette of the parachutist, often accompanied by glimpses of the parachute gear above. The glory itself arises from the diffraction and scattering of sunlight by minuscule water droplets within the thin clouds beneath the parachutist.

The Sublime Fogbow

While rainbows are widely known and admired, their lesser-known cousin, the fogbow, possesses its own unique allure. Fogbows share similarities with rainbows but are slightly smaller in size. Picture a delicate arc of pastel hues gracefully spanning the sky amidst a veil of fog or mist. The ethereal beauty of a fogbow lies in its subtlety and evanescent nature.

By estimating the radius of a fogbow, typically around 39°, we can deduce the approximate radius of the accompanying glory, which measures approximately 3.5°. Such calculations provide valuable insights into the size and characteristics of the cloud droplets responsible for these optical marvels. Surprisingly, the mean diameter of these droplets is estimated to be around 12 microns (0.012mm), significantly smaller than raindrops.

Unveiling the Science

The captivating display of glories and fogbows during parachute descents arises from the interaction between sunlight, thin clouds, and minuscule water droplets. Understanding the science behind these phenomena deepens our appreciation for the wonders of atmospheric optics.

Here's a breakdown of the process:

• Sunlight passes through the atmosphere, encountering clouds beneath the parachutist.
• Within these clouds, tiny water droplets act as miniature prisms, diffracting and scattering sunlight in various directions.
• Some of this diffracted light is directed back towards the observer's camera or eye, forming a glory around the shadow of the parachutist.
• The diffraction process also contributes to the creation of fogbows, where sunlight undergoes additional scattering and reflection within the fog or mist, resulting in a delicate arc of colors.

Exploring the Parachutist's Perspective

If you find yourself on a parachute adventure, keep an eye out for glories and fogbows. However, it's important to note that there may be instances where focusing on other matters takes precedence over observing these optical phenomena. Safety should always remain the top priority during any aerial activity.

Nevertheless, when conditions are favorable, take a moment to gaze upwards and immerse yourself in the enchanting dance of light and clouds. The interplay between parachutes and the atmosphere offers a unique vantage point to witness nature's artistry firsthand.

In Conclusion

Parachute optics provide a gateway to an enchanting world of atmospheric phenomena. The juxtaposition of parachutists against the backdrop of thin clouds gives rise to the mesmerizing glories and fogbows that grace our skies. By understanding the underlying science, we can truly appreciate the beauty and intricacies of these optical wonders. So, the next time you embark on a parachute adventure, keep your eyes peeled for the captivating interplay between sunlight, clouds, and the ethereal displays of glory and fogbow.

Parachute Optics

Marcus Price sent in these images of his son parachuting in New Zealand.-

There is thin cloud beneath. Its tiny water droplets diffract and scatter sunlight back towards the camera to form a colourful one-ringed glory and A huge fogbow.

Inside the glory we can see the "Brocken Spectre" shadow of the parachutists and above them part of the chute gear. Glories are always directly opposite the sun: Just where the shadow of your camera or eye falls.

Fogbows are slightly smaller than rainbows. From this fogbow's approximate size, say 39° radius, we can find the radius of the glory. It comes out as about 3.5°.

That fixes the mean cloud droplet diameter as around 12 micron (0.012mm). At the smaller end of cloud drop sizes and rather smaller than raindrops!

Next time you are on a parachute look out for glories and fogbows.

But there are occasions when it is advisable to concentrate on other matters.

At right there is a glory just to the left of the parachute that has failed to open. See here for more.

Note: this article has been automatically converted from the old site and may not appear as intended. You can find the original article here.

Reference Atmospheric Optics

If you use any of the definitions, information, or data presented on Atmospheric Optics, please copy the link or reference below to properly credit us as the reference source. Thank you!