Mystery Rainbow?

Semi writes: Okay, not what you normally think of as UFOs, but a strange apparition. I work at UVA Hospital, and the sound of Pegasus coming in caused me to look up, and I saw the most remarkable thing (about 2:45 pm on 11/25 as I write this). A rainbow! But not your typical Hollywood horizon-to-horizon rainbow. This one was almost straight up in the sky and I could see both ends of it, like a big C. It was nearly 180 degrees, somewhere between 120 and 150. It was not a corona (or whatever you call those dark hued rings that appear round the sun); this was a full-fledged prismatic rainbow, bending away from the sun. Unfortunately, in the ten minutes it took me to walk back to desk and get to my computer, it was practically gone. To see it, go outside and look almost straight up, just a little south and east in the general direction of the sun. Did anyone else see this? Any meteorologists on this site who can explain it? Am I just flashing back to the sixties? Curious minds want to know..

14 thoughts on “Mystery Rainbow?”

  1. Maybe it was a corona……12 coronas! Ease up on the alcohol pal. Then again, this was 4th year 5th weekend! (just kidding)

  2. If I understand your description correctly, you observed a circumzenithal arc.

    Check out this link and tell me if that’s what you saw…

    If it’s not, that site has descriptions, pictures, and explanation of the physics of all the other sorts of displays, so you should be able to find what you saw and put a name to it!

  3. The description of a circumzenithal arc from the above-linked site:

    "The circumzenithal arc is the most beautiful of the halos. The first sighting is always a surprise, an ethereal rainbow fled from its watery origins and wrapped improbably about the zenith. It is often described as an "upside down rainbow" by first timers. Someone also charmingly likened it to "a grin in the sky".

    Look straight up near to the zenith. The bow points sunwards. It is never a complete circle around the zenith, that is the extremely rare and never photographed "Kern arc". "

  4. I saw it at about 1PM from in front of City Hall.

    It was more like a "right-side up" rainbow. Not upside down like that link shows.

    I took it to be a form of "sun dog" wich more often appears just as a pair of rainbow-colored patches, one on each side of the sun.

    Pure speculation follows: If the condition that causes "sun dogs" to appear exists as a layer in the atmosphere through which the sunlight refracts, then perhaps today’s phenomenon was a thicker layer and/or multiple layers.


  5. Based on what I saw it looked most like the “supralateral arc” or the “46 degree halo” shown in the illustration here.


  6. Oh… <reads the original post again> wow that sounds way cooler than what I saw. Shoulda taken a longer lunch, I guess.


  7. this just reminded me of something i saw last spring…

    i stepped out onto the mall after some heavy rain had

    just ended, and the light outside was absolutely incredible –

    this was probably around 4 or 5pm – i ran up to the roof

    of the water street parking garage, and looked up to see

    two huge, completely circular rainbows around the sun-

    a set of two concentric circles of rainbows. i tried to take

    a picture but my camera was out of film and i’m fairly sure

    it wouldn’t have photographed well anyway.

  8. Ummm, the simple explanation is crystals are cool, and crystals of ice in the atmosphere make cool things happen to light.

    The complete explanation is that the ice crystals that form in the upper troposphere are a hexagonal crystal with a sixfold rotational symmetry. This hexagonal prism diffracts light within its structure. Since each color wavelength bends at a slightly different angle, white light separates into many colors.

    Here is where it gets tricky… If the incoming light penetrates the sides of the hexagonal plates at a 60 angle, the light is bent to 22, which we see as a circle of light or halo at 22 from the sun. If the light just happens to pass through the ends of the ice crystals where a 90 prism angle exists, the light refracts at 46 and we can see a twin rainbow at that angle. Since its more likely that light passes through the sides of a crystal than its ends, we see the 22 halo more frequently.

    Due to the random orientation of ice crystals and the random chance of crystals hitting the light just right, the colors in most halos are not very intense. It’s important to remember that we each see our own, personal rainbow and it’s entierly dependent upon our position relative to the sun and the ice crystals. If the sun is higher than 42 in the sky, we cant see a rainbow.

    P.S. Actual post-rain-storm rainbows use a spherical prism. It has perfect rotational symmetry, which makes for an excellent rainbow. Usually the sun is behind us in late afternoon after a rainstorm.

  9. P.S. Actual post-rain-storm rainbows use a spherical prism. It has perfect rotational symmetry, which makes for an excellent rainbow. Usually the sun is behind us in late afternoon after a rainstorm.

    You mean “usually the rainbow is opposite the sun, in the late afternoon after a rainstorm.”

  10. I was out riding my bike and I saw it as well. Quite an unusual site, and I think it is only the second time I have ever seen a rainbow stretch from point to point along the horizon. Incidentally, the wind and rain picked up rapidly, screwing up my bike ride, but then it did spur me to ride quickly. ;)

  11. I saw that guy with a sign on the back of his bike saying "You’d be happier on a bike" during a downpour.

    And I thought to myself, "No, I would NOT be happier on a bike".

  12. I saw that one too… took a few pictures but haven’t sent the film in yet. hopefully something will show up on the picture

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