Astrophoto: Double Crepuscular Rays

by Nancy Atkinson on June 10, 2012

Want to stay on top of all the space news? Follow @universetoday on Twitter

Crepulscular rays appear simultaneouly on both the west (left) and east horizon at sunset on June 9, 2012. Credit: Nancy Atkinson

I’m not sure how often this happens, but I’ve never seen it before: crepuscular rays on both the west and east horizon at the same time — or crepuscular and anti-crepuscular rays occurring simultaneously. I’m staying out in the wilds of Minnesota this summer, with great views of both horizons and captured these images last evening, June 9, 2012. The word crepuscular means “relating to twilight,” and these rays occur when objects such as mountain peaks 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 so that sunlight in unshadowed areas can be 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.
Anyone else ever seen this before?

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. One of the astronauts on the International Space Station actually captured crepuscular rays from orbit, showing how the rays are actually parallel. You can see that image and the description here.

Below are the two images separately. It was a beautiful evening and a thrilling sight.

Sunset crepuscular rays on the west horizon on June 9, 2012. Credit: Nancy Atkinson

Anti-crepuscular rays on the east horizons on June 9, 2012. Credit: Nancy Atkinson.

About 

Nancy Atkinson is Universe Today's Senior Editor. She also is the host of the NASA Lunar Science Institute podcast and works with Astronomy Cast. Nancy is also a NASA/JPL Solar System Ambassador.

Brent Bozo June 10, 2012 at 4:19 PM
MayerTheresa June 11, 2012 at 3:04 AM

Have you ever wanted to earn cash online? That’s why I would like to tell you a website where the owner shares all ways of making money online. Did you know that you can make money trying products or clicking ads? Then you should visit ====>>> ?????? (Click At My Name For Link)

GardnerDennis June 11, 2012 at 7:03 PM

my best friend’s sister-in-law got paid $14696 the prior month. she is making money on the inte<!–truth is almight–>rnet and bought a $372500 home. All she did was get blessed and work up the steps uncovered on this link

?????? (Click At My Name For Link)

RatliffSandy June 10, 2012 at 7:02 PM

Have you ever wanted to earn cash online? That’s why I would like to tell you a website where the owner shares all ways of making money online. Did you know that you can make money trying products or clicking ads? Then you should visit ====>>> ?????? (Click At My Name For Link)

Stefan Lamoureux June 10, 2012 at 11:15 PM

We came down from Lappland and the Sun was not rising or setting, as we drove more south, the Sun rose up and at the opposite horizon was this rainbow of only red disfraction light, no other colors. as we stopped we saw it was a double rainbow. Could have the rainbow started as a crepiscule ray and then formed a rainbow? Here a link to the picture.
http://linksthroughspace.blogspot.fi/2012/06/transit-of-venus-2012-return-home.html

Karthik Vj June 11, 2012 at 11:51 AM

I could see two rainbows in that picture..

Comments on this entry are closed.

Previous post:

Next post: