Can anyone explain the pilot's rainbow? Why, just prior to entering a cloud, is there a mirror image of the aircraft, with a rainbow surrounding it?

A Pilot's rainbow isn't a rainbow, it's a glory. A rainbow is part of a rain-glory (ie a 'bow' of it). Since the pilot's rainbow is caused by cloud, it isn't a bow, or due to rain. It's a glory :p

The sun refracts through the water droplets in the cloud in the same way it does with rain, forming a 42 or 32(I forget which) degree cone of light, with red refracted more than blue, so the red is seen outermost, and the blue innermost (simply put).

The 'image' of the aircraft is just the shadow of the aircraft... because the center of a rainbow or glory is opposite the sun... so it has to be in the center :)

Hope this helps, let me know if you need further understanding.

The 'image' of the aircraft is just the shadow of the aircraft... because the center of a rainbow or glory is opposite the sun... so it has to be in the center :)

I'd buy this, since the sun is behind you, however, I have a couple of photos, where the 'image' has visible faces of the people sitting up front.


Have any references with more detail?

Does the glory perform differently when the water is crystals, as ice?

Is a glory related to how the ground always looks brighter in the vicinity of the aircraft shadow?

Could you scan and host the photos, I would love to see them

The brighter ground is because all wavelengths of light are refracted once you get to the center, so you get extra white light refracted as well as the light reflecting normally. You can see this in normal rainbows, and is not unique to glories.
Next time there is a rainbow, notice that the sky inside the bow is brighter than that outside.

I don't think you would see a glory in ice, the particles would not be spherical, which is needed to produce the refractive effect. If they were spherical I think it would just make the glory bigger or smaller (different refractive index). I don't think it would add mirroring to the glory.

I haven't looked at any references, this is all my own understanding.

You can see the brighter inside here: http://www.alanbauer.com/photogaller...Inlet-Horz.jpg

Also notice the faint secondary bow, due to a 3rd reflection inside the droplet, I'd love to know if any of your photos have secondary glories?

Most people never notice these extra features of rainbows - they're happy enough appreciating the colors :)

The images I have, which are any good are Kodachrome 25 slides, taken over 25 years ago. They clearly show the second glory. Shots taken with conventional color print film lack sufficient gamut to show all the detail, as well as the "reflection".

Three years ago, while positioning over Niagara Falls, to shoot the falls through a "hole" we shot some glories with HD. I thought it would have sufficient dynamic range to handle things, but it didn't. Either that, or the LUTs were suboptimal.

I tried scanning in the slides several year ago, and the scanner I had available did not have the range/quantization to show all the detail, like the faces in the plane. I'll dig and see if I have some others which might work, but I don't think so. I haven't gone completely digital (grin).

Thanks.

Thanks, I'd love to see the reflection.

If you have any further questions be sure to ask :)

How do you view the slides? On a projector?

Could you use a camera to take a photo of the projection?

Yes, the slides were viewed on a projector. Quite a few people have seen them, and the reflections. Someone once had an explanation for the reflection, but I didn't understand it.

Sometimes I get a very good film scanner available, and when I can get it, I will scan in the cloud penetration sequence. It was taken over Blacksburg VA in 1978. I have some others but they are not quite as good.

Unless the image is processed, you'd get something like a 12 bit per color image. With that gamut you can clearly see the reflection. If I simply took a digital picture of a screen, while projecting the slide, it is likely that you would not be beable to see the faces.
Remember, the shot was taken with the camera pointed at a white cloud, with the sun behind it. The faces are inside the darker cockpit of a white plane. When looking at the orig, there are actually two sets of faces, because there is a reflection off the internal plexiglas of the windshield, however, those are curved and distorted by the interior geometery of that surface.

Looking forward to it :)