Categories: Astrophotos

Timelapse: Anticrepuscular Rays at Monument Valley

Astrophotograher César Cantú from Mexico is visiting Utah and captured an incredible timelapse of the view at sunset along with the formation of anti-crepuscular rays — a spectacular optical phenomena where light rays scattered by dust and haze appear on the horizon opposite to the setting Sun.

The word crepuscular means “relating to twilight,” and these rays occur when objects such as hills or clouds partially shadow the Sun’s rays, usually when the Sun is low on the horizon. These rays are visible only when the atmosphere contains enough haze or dust particles and in just the right conditions, sunlight is scattered toward the observer.

Then occasionally, light rays scattered by dust and haze sometimes appear on “antisolar” point, (the horizon opposite to the setting Sun). These rays, called anti-crepuscular rays, originate at the Sun, cross over the sky to the opposite horizon, and appear to converge toward the antisolar point.


For both crepuscular and anti-crepsucular, the light rays are actually parallel, but appear to converge to the horizon due to “perspective,” the same visual effect that makes parallel railroad tracks appear to converge in the distance.

Above is an image I took a few years ago when I captured both crepuscular and anti-crepuscular rays at the same time. You can read about that here.

Here’s a a great night sky shot of Monument Valley from César:

Monument Valley in Utah under the starry night sky on May 27, 2014. Credit and copyright: César Cantú.

See more of his images here.

Want to get your astrophoto featured on Universe Today? Join our Flickr group or send us your images by email (this means you’re giving us permission to post them). Please explain what’s in the picture, when you took it, the equipment you used, etc.

Nancy Atkinson

Nancy has been with Universe Today since 2004. She is the author of a new book on the Apollo program, "Eight Years to the Moon," which shares the stories of 60 engineers and scientists who worked behind the scenes to make landing on the Moon possible. Her first book, "Incredible Stories from Space: A Behind-the-Scenes Look at the Missions Changing Our View of the Cosmos" tells the stories of those who work on NASA's robotic missions to explore the Solar System and beyond.

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