Airplane glory: What is it and how to spot one?

Airplane glory: Easy and surprising!

I was looking out the window of an airplane recently, and I saw the airplane’s shadow on a cloud. A rainbow seemed to surround it. What was it?

It sounds like the beautiful optical phenomenon known as the glory, also called an anti-corona or pilot’s bow.

Glories are common. People traveling in airplanes see them all the time. You need the sun to be directly behind your head. In front, you need an ordinary cloud. As you look toward the cloud, look for the shadow of the airplane. A multi-colored circle of light will surround the plane’s shadow. That light is the glory.

The plane’s shadow doesn’t have anything to do with making the glory. The glory and the shadow just happen to be located in the same direction … opposite the sun.

Here’s what makes a glory

In other words, like a rainbow, a glory is centered on the antisolar point, which coincides with your head’s shadow. And it coincides with the larger shadow of an airplane, if you’re looking out of an airplane window. So this point – the point where you’ll see the glory – must be opposite the sun’s position in the sky.

You might see that, when the sun is high in the sky and you’re on the ground, the antisolar point always lies below your horizon. That’s why, in order to see a glory, the clouds or fog causing it have to be located below the observer, in a straight line with the sun and the observer’s eye.

Want more about what makes a glory? Try this page from Les Cowley of the great website Atmospheric Optics.

Where else you might see a glory?

Nowadays, most people see glories from airplanes. But they’re also commonly observed from very tall buildings. And, before the days of air travel, people spoke of glories they’d seen while mountain climbing. The same conditions – the sun behind and a cloud ahead – can also cast your shadow onto a mist while you’re scaling a tall peak. Then it’s possible to see a glory around the shadow of your own head. That type of glory is called a brocken spectre.

The glory is round, like the halo you sometimes see around the sun or moon. And it comes in muted rainbow colors.

Some glory photos from our EarthSky Community

Bottom line: An airplane glory is easy to see if you watch for it while traveling by air. The sun has to be behind your head. You’ll see the plane’s shadow cast on a cloud. And a halo of light will surround the shadow.