View at EarthSky Community Photos. | Ron Haggett in Yuma, Arizona, captured this photo of crepuscular rays and anticrepuscular rays on the morning of September 1, 2021. He wrote: “These 2 images show crepuscular rays (left) and anticrepuscular rays (right). These photos were taken 9 minutes apart (6:00 and 6:09 am, local time). Crepuscular rays are sunbeams that originate when the sun is below the horizon during twilight hours. The image on the left is looking due east just before sunrise. Sunbeams can also extend across the sky and appear to converge at the antisolar point, the point on the celestial sphere opposite the sun’s direction. In this case, they’re called antisolar rays. The image on the right is at the antisolar point (due west). The earth’s shadow (dark blue at the horizon) and the Belt of Venus (dark pink above earth’s shadow) can also be seen in this image.” Thank you, Ron!
What are crepuscular rays?
Crepuscular means like twilight or dim. This phenomenon occurs around sunrise or sunset, when the sky is somewhat dark. Crepuscular rays may appear to fan across the sky, but the rays are really parallel to each other. The sunbeams appear to diverge, much as a road that looks narrow in the distance appears wide beneath your feet. Airborne dust, droplets of water and the air molecules themselves are what make the sunrays visible. Next time you see them, remember to turn around. You might be in luck and see fainter and less noticeable anticrepuscular rays.
Crepuscular rays can also go by the name of sunray. Some people also apply the term crepuscular ray for sunbeams that radiate from the direction of the sun while it is still above the horizon but hidden behind clouds. Although technically, a crepuscular ray requires the sun to be below the horizon. The photos of sunbeams coming from a sun still above the horizon also have the nickname Jacob’s Ladder. The term comes from a story in the bible where Jacob has a dream in which he sees a ladder leading up to the golden light of heaven with angels ascending and descending.
All of these photos were contributed by EarthSky friends. Thanks for sharing your awesome photos with us!
Photo gallery of crepuscular rays
View at EarthSky Community Photos. | Brendan Barnes captured crepuscular rays running all the way across the sky in this panoramic photo taken in Guam on October 28, 2020. He wrote: “I woke up this morning to bright pink clouds outside my window, so I ran upstairs to the roof and found crepuscular rays going the entire way from the rising sun toward the horizon to the west!”Sunrays over the Gulf of Mexico. Photo via Rick Trommater.Photo via Lewistown Storm Watcher.
Photos of Jacob’s Ladder
Image via Nicholas Holshouser.Marble View, Kaibab National Forest, Arizona. Image via Gaelyn Olmsted.Image via Mark Hunter.Image via Robin Reilly.Prince Rupert, British Columbia, via footeprints unlimited. Image via Allison Lewis.Image via Steve Case in the U.K.Photo via Howard Harner.Western Colorado. Photo via Allen Lefever.Lake Garda in Italy, by Luca Milevoj. Thank you, Luca.
Moon rays or Moonbeams
James Younger frequently camps at Vancouver Island and catches many wonderful sky sights from its shores. He captured these moon rays in August 2017.
Bottom line: Crepuscular rays form when the sun is below the horizon but light beams streak into the darkening sky. Anticrepuscular rays are on the horizon opposite the sun.
Eleanor Imster has helped write and edit EarthSky since 1995. She was an integral part of the award-winning EarthSky radio series almost since it began until it ended in 2013. She and her husband live in Tennessee, where they enjoy guitar playing and singing. They have 2 grown sons.
Deborah Byrd created the EarthSky radio series in 1991 and founded EarthSky.org in 1994. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. "Being an EarthSky editor is like hosting a big global party for cool nature-lovers," she says.
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