Explained at NASA's Astronomy Picture of the Day website:
Explanation: Yes, but can your rainbow do this? Late in the day, the Sun set as usual toward the west. However, on this day, the more interesting display was 180 degrees around -- toward the east. There, not only was a rainbow visible, but an impressive display of anticrepuscular rays from the rainbow's center. In the featured image from Lekeitio in northern Spain, the Sun is behind the camera. The rainbow resulted from sunlight reflecting back from falling rain. Anticrepuscular rays result from sunlight, blocked by some clouds, going all the way around the sky, overhead, and appearing to converge on the opposite horizon -- an optical illusion. Rainbows by themselves can be exciting to see, and anticrepuscular rays a rare treat, but capturing them both together is even more unusual -- and can look both serene and surreal.
A dozen relevant links at the source.
Addendum: the most amazing fact is that those anticrepuscular rays are NOT converging in the distance. All of them are PARALLEL lines. The "convergence" is an optical illusion similar to railroad tracks or highways extending into the distance.
Lekeitio is about 45 minutes from my home in San Sebastián. While we did not receive the quite the spectacular cloud formation that day, the rainbow was the brightest and widest I've ever witnessed and after about 30 minutes was an complete arc. Oh yeah, the day before we were all stuck inside with gale force winds, horizontal wind and hail.
ReplyDeleteReminds me of a memorable sunset on a lake in the Cascades a few years ago. The western sky was amazing, but to the east, spectacular cloud/sky color (partly due to wildfire smoke), a rainbow and dry lightning all at once.
ReplyDeleteI was in Asseteague NS recently, and had a similar situation. Gorgeous golden sunset with crepuscular rays in the West, and a full 180 degree rainbow on the other end when the sun peaked under the clouds. All that over a half frozen swamp with wild horses. Oh, and a bald eagle nesting in the far distance.
DeleteIt was cold AF*, but so worth standing there nearly alone for a good hour.
* totally aware that east-coast cold AF is balmy for the upper Midwest. That ocean breeze was bone-chilling though.
Very cool. And every vista with wild horses is somehow magical. I think they refuse to participate in anything less.
Delete'Anticrepuscular' ... threw mi sum watt.
ReplyDeleteLike, 'against the gloaming' ?
Or 'opposite of the waking and sleeping of the ocular world' ?
You could look it up -
Deletehttps://en.wikipedia.org/wiki/Anticrepuscular_rays
"Crepuscular" means "related to twilight", since that's when these rays most often occur. The "anti" part indicates that they are seen in the opposite part of the sky of where the sun is. (When the rays are seen in the direction of the sun, they are called just "crepuscular rays". The terminology is admittedly a little clumsy, because they're the exact same phenomenon, except for the direction in which they are observed.)
DeleteI should add that you can use the term in occasional conversations by referencing "crepuscular animals" (those that are not diurnal or nocturnal) -
Deletehttps://en.wikipedia.org/wiki/Crepuscular_animal
Even way more interesting is that those crepuscular rays are NOT converging in the distance. They are PARALLEL lines. (I've added that - with a link - to the main text)