Shape-Changing Light From Plane with Nikon P900 - Polarizing filter + Venus?

[Mick West]

Source: https://www.youtube.com/watch?v=IF3w0kI53aU




Just looks like Venus at sunset? But when zoomed in, it takes on all kinds of shapes


I've got a P900. To me these all look like some kind of optical distortions of a small light source (i.e. Venus). However I've not seen anything this extreme before, and I wonder what's actually going on. The shapes seem relatively stable, so that seems to rule out the normal atmospheric turbulence. Camera shake and zooming don't really seem to change the shape, and we don't see it actually change shape often, that seems to be off-screen.

It's possible someone is deliberately inducing the distortion with something on the filter, like water drops

One interesting things at 5:52:



Motion blur, but structure in the blur, which implies some kind of fixed periodic movement. Possibly a faulty image stabilization?

A puzzle.

 

[deirdre]

this guy has some somewhat similar shapes, fairly stable... not as crisp as hers but he says what he is doing
Source: https://www.youtube.com/watch?v=itUvuSemM3o


ex:

 

[MclachlanM]

More stars filmed from plane windows with P900s, they all get similar weird effects that you don't seem to get with footage from the ground:
Source: https://www.youtube.com/watch?v=Sz4aiT61dfs

Source: https://www.youtube.com/watch?v=L_RjwOpMzMg

Source: https://www.youtube.com/watch?v=IRo2XsfWVwA


Perhaps what's really happening here is we're seeing a very small crystal of ice on the plane window illuminated by the small point light of a star?

Edit: A couple of people on the UFO reddit have already brought up the idea of this just being the light of Venus refracted by the glass of the plane, perhaps someone with an expensive camera could do an experiment by freezing glass and then attempting to recreate these kinds of shapes?

 

[LilWabbit]

It looks more like the light of Venus refracted by some high-altitude atmospheric effects or sub-visible clouds which to the naked eye, and against no source of light, would seem indistinguishable from a clear sky.

 

[Mick West]

Perhaps what's really happening here is we're seeing a very small crystal of ice on the plane window illuminated by the small point light of a star?

Edit: A couple of people on the UFO reddit have already brought up the idea of this just being the light of Venus refracted by the glass of the plane, perhaps someone with an expensive camera could do an experiment by freezing glass and then attempting to recreate these kinds of shapes?

The issue here is that the shapes are very stable, even when the camera seems to be shaking around.

 

[Mick West]

this guy has some somewhat similar shapes, fairly stable... not as crisp as hers but he says what he is doing

Polarizing filter. Hmm, one sec....

Nope. Tried taking video of a star from ground level. Nothing like that.

 

[LilWabbit]

Three facts:

(1) The denser part of the atmosphere is only 10 miles thick.
(2) The atmosphere consists of various gases.
(3) The airplane is constantly moving.

So if Venus is seen horizontally or subhorizontally from an airplane through the tropopause (average height 36,000 feet / 7 miles according to International Standard Atmosphere), the light from Venus travels a greater distance through dense atmosphere to the camera lens than when viewed from ground angles. The constant movement of the airplane may further compound the shape-shifting effect.

Could this explain the optical effect when viewed from a fast-moving airplane? In other words, the effect would still qualify as atmospheric refraction. However, due to the horizontal/subhorizontal angle in high altitude and the constant motion, the refraction effect and dispersion looks quite different from what we're used to.

It's actually hauntingly beautiful.

P.S. There could also be a very faint subvisible cirrus layer within/through which the airplane is flying:

 

[jarlrmai]

This is taken through plane window right, so there's 2 layers of thick slightly curved optically flawed plane window glass in front of the lens?

 

[LilWabbit]

This is taken through plane window right, so there's 2 layers of thick slightly curved optically flawed plane window glass in front of the lens?

If it's the window, then the camera zooming would render the image less stable than it does. The shape-shifting seems more a function of high-altitude atmospheric refraction acting together with the constant movement of the plane.

 

[FatPhil]

The issue here is that the shapes are very stable, even when the camera seems to be shaking around.

The shapes remind me of the astygmatism distortions. If you're slightly misfocussed, then you'll get anything from a diamond (equally out of focus in both directions) to a barbell shape (one axis much more in focus than the other), and if you're not changing focus, those will be stable. More out of focus, and the more normal bokeh disks will return (so of course there are intermediate shapes between barbells and disks).

 

[deirdre]

Nope. Tried taking video of a star from ground level. Nothing like that.

well he's doing something youre not. keep playing around.

 

[AmberRobot]

this guy has some somewhat similar shapes, fairly stable... not as crisp as hers but he says what he is doing
Source: https://www.youtube.com/watch?v=itUvuSemM3o


ex:

You can see the astigmatism as he moves through focus towards the end. We don’t know the quality of the lens and especially the filter, which seems to introduce some wavefront error.

 

[Ravi]

100% astigmatism ie distortion of the wavefront. The more point-like the source, the flatter the wavefront, and thus the most easy to get influenced by non perfect refractive elements. The window is the culprit imo.

 

[deirdre]

one real camera site i was reading says you need to manually turn the polarize lens to get optimum/different results. not sure if that would do anything in addition to a manual focus. ??

add: and maybe a lil fingerprint smudge of hand sanitizer

 

[AmberRobot]

100% astigmatism ie distortion of the wavefront. The more point-like the source, the flatter the wavefront, and thus the most easy to get influenced by non perfect refractive elements. The window is the culprit imo.

I can’t imagine an airplane window is going to be friendly to a wavefront.

 

[LorentzHall]

These kind of photographs are called refractographs.

 

[LilWabbit]

These kind of photographs are called refractographs.

Things of beauty. I think at this point we all seem to agree the shapes are a result of refraction of some kind. Refraction through window, lens or atmosphere (or a combination of all).

In the refractograph tutorial the video image after the setup (while he is demonstrating different filters in front of the camera) doesn't shift shapes. The same is true to the patterns in the lens-polarization footage.

So if indeed it's refraction through the plane window, the shape-shifting could be caused simply by the movement of the plane.

Still feeling iffy about the plane window hypothesis though. The camera movement and zooming would affect the pattern and yet they don't seem to.

 

[LorentzHall]

The P900 uses a 16 element lens.

The longer the focal length of a lens, the more difficult it is to correct image aberrations of all many sorts. They might compound internally.

 

[AmberRobot]

The longer the focal length of a lens, the more difficult it is to correct image aberrations of all sorts.

That’s not generally true, as there are aberrations that depend on beam speed (focal ratio) such that for a fixed aperture size, longer focal length (I.e., “slower”) systems have less aberration content.
For much the same reason that stopping down your lens can improve image quality.

 

[Ashley Pomeroy]

If it's the window, then the camera zooming would render the image less stable than it does. The shape-shifting seems more a function of high-altitude atmospheric refraction acting together with the constant movement of the plane.

At 01:25 (for example) it looks as if the zoom effect is digital zoom, e.g. the camera is enlarging the image digitally rather than racking the lens elements. The grain gets bigger, which doesn't happen with optical zoom.

That would explain why the aberration occasionally seems to remain the same shape, which you wouldn't expect if the lens elements were moving back and forth. The P900 is famous for its enormous optical zoom range but it also has 4x digital zoom.

 

[Radapox]

The issue here is that the shapes are very stable, even when the camera seems to be shaking around.

As someone who wears glasses, these shapes are all too familiar. It's what you get when looking at a bright object at night through water droplets that have accumulated against the glass. The shapes show the exact same stability regardless of movement as you observed here.

Marcel Minnaert has a section on the phenomenon (emphasis mine):

118. Interference Phenomena in Raindrops



Many people obliged to wear glasses out-of-doors complain that raindrops distort the images and make them unrecognisable. It may perhaps console them if we call their attention to the splendid interference phenomena visible in these same raindrops. All they need to do is to look at a source of light in the distance-a street-lamp, for example. A raindrop that happens to be exactly in front of the pupil becomes strangely distorted, a spot of light with extraordinary projections and indentations, with a border of very beautiful diffraction fringes in which colours, too, are distinguishable (Fig. 104, a). One remarkable thing about it is that the spot of light remains in the same place even when the eyeglass is moved slightly to and fro. Another is that the general shape and protruding curves of the spot of light seem, at first, to bear no relation whatever to the shape of the raindrop. The explanation is simple. Regard the eye as a small telescope forming an image of a source of light in the distance, and the drop of water as a group of small prisms held in front of the objective. It is then clear that each small prism refracts a group of rays laterally, independently of its position on the objective (provided it is still within the opening of the objective); the shape of the light-patch will depend, however, on the value of the refracting angle and on the orientation of each small prism. A drop of water extended vertically does indeed give a horizontal streak of light.
But now the diffraction fringes! These would not exist if the drop of water formed an accurate lens and so imaged the source of light exactly at a point, for then all parts of the light wave-front, since they left the source simultaneously, would arrive at the image together with no change of relative phase. But since the surface of the water is curved irregularly the refracted rays do not meet in a focus, but are enveloped by a caustic (Fig. 104, b). In such a case one always finds that through a point in the neighbourhood of the caustic there pass two different rays which have traversed light-paths of different lengths; interference therefore occurs. On drawing the wave surface one finds a point of reversal giving a cusp; at any moment, therefore, there will always pass through a point T two wave-fronts with a definite difference of phase (Fig. 104, c).

Marcel Minnaert, The Nature of Light and Colour in the Open Air (Dover Publications, 1954, translation H. M. Kremer-Priest, revision K. E. Brian Jay), §118, Interference Phenomena in Raindrops (pp. 167-169). The Dutch original can be found online here: https://www.dbnl.org/tekst/minn004natu01_01/minn004natu01_01_0011.php

So, long story short, I think there's moisture on the lens.

 

[LilWabbit]

As someone who wears glasses, these shapes are all too familiar. It's what you get when looking at a bright object at night through water droplets that have accumulated against the glass. The shapes show the exact same stability regardless of movement as you observed here.

Marcel Minnaert has a section on the phenomenon (emphasis mine):


So, long story short, I think there's moisture on the lens.

Very interesting! But how do you account for the slow and somewhat steady shape-shifting though? The movement of the plane affecting the angle perhaps?

 

[Radapox]

Very interesting! But how do you account for the slow and somewhat steady shape-shifting though? The movement of the plane affecting the angle perhaps?

I'm not entirely sure, but that would make sense. As far as I understand it, movement does cause some small distortions to the overall shapes.

 

[Bill Ferguson]

I was excited about this one but based on the videos and discussion posted above, this effect is well known (especially with the P900) and can be easily reproduced under the right conditions. Thanks for debunking this one.

 

[JMartJr]

Very interesting! But how do you account for the slow and somewhat steady shape-shifting though? The movement of the plane affecting the angle perhaps?

I'm not entirely sure, but that would make sense. As far as I understand it, movement does cause some small distortions to the overall shapes.

Water droplets also evaporate over time, changing their size and presumably the optical distortions that they create. Air in planes is notoriously dry.

 

[jarlrmai]

Planes also vibrate somewhat when cruising.

 

[LilWabbit]

Water droplets also evaporate over time, changing their size and presumably the optical distortions that they create. Air in planes is notoriously dry.

If we can get footage of a similar type of somewhat steadily shape-shifting refraction rather than still refractions, then we're closer to a full debunk. If its water droplets, it shouldn't be too difficult to demonstrate. Somehow I feel the OP footage is a more complex refraction with a combination of refractors, together with the plane movement, creating the shape-shifting patterns.

 

[JarJar]

Strange...I see similar aberration focusing my telescope when the primary mirror starts fogging up, or if there is a lot of atmospheric noise.

Not sure how a plane window affects the focus. They have several layers.

 

[antiwesley]

Let's also not forget that if the person is sitting behind the wing, and there is a jet engine just in front of them... HEAT.
Heat distorts images, and that could explain a lot of it.

 

[Ravi]

Looking at the video Mick has linked in post #1, (Source: https://www.youtube.com/watch?v=IF3w0kI53aU)

When you see the transformation going on of the blob @ 6:46, I can only conclude it is caused by optics. Can be the window (quite dirty!) or the camera itself, but for sure it is caused by imaging.

 

[AmberRobot]

Looking at the video Mick has linked in post #1, (Source: https://www.youtube.com/watch?v=IF3w0kI53aU)

When you see the transformation going on of the blob @ 6:46, I can only conclude it is caused by optics. Can be the window (quite dirty!) or the camera itself, but for sure it is caused by imaging.

Indeed, as someone who has spent time trying to make optical systems focus on bright point sources (former astronomer), I can say that this looks almost exactly like what an out of focus point source looks like.

The real question is what is happening to cause the slow variations. Either the camera itself is slowly adjusting focus or the camera holder is doing it manually. It’s too bad the holder didn’t rotate the camera and see how the pattern rotated with it or not.

 

[Ravi]

Indeed, as someone who has spent time trying to make optical systems focus on bright point sources (former astronomer), I can say that this looks almost exactly like what an out of focus point source looks like.

The real question is what is happening to cause the slow variations. Either the camera itself is slowly adjusting focus or the camera holder is doing it manually. It’s too bad the holder didn’t rotate the camera and see how the pattern rotated with it or not.

I looked up the optical design, perhaps of interest. Looks to me like a complex design (5 moving groups), and perhaps could be vulnerable to small mis-alignments? Perhaps that can cause the aberrations? Hmmm.. not sure though..





source: https://nikonrumors.com/2016/09/18/...e-nikon-coolpix-p900-camera-replacement.aspx/

 

[AmberRobot]

Every optical system will have some amount of aberration content. A zoom lens like this has to balance good imaging over a wide range of focal lengths and focus settings. (Astronomical observations are done with fixed focal length systems with high quality optics.) Typically, the more a lens is designed to do the harder it will be to do it all very well.
Looking at Amazon, a Nikon P900 camera is about $900 and that’s for the body and the lens. That’s cheaper than a lot of high quality zoom lenses (just the lens). So my guess is that they’re doing the best they can to balance the aberrations while keeping the engineering, lens quality, alignments, etc at reasonable cost and effort. A point source will show you the limitations of your optical system. And stars and planets can be difficult to focus on, especially at high zoom, unless you’re very experienced, and even if you are. Because the shapes being seen look like out of focus aberrated point images, I’m disinclined to believe that it’s anything but that. I can’t explain the exact shapes that are seen but I’d bet they’d be related to various types of aberrations like astigmatism, coma, trefoil, etc.

 

[Peacechief]

Looking at Amazon, a Nikon P900 camera is about $900 and that’s for the body and the lens. That’s cheaper than a lot of high quality zoom lenses (just the lens). So my guess is that they’re doing the best they can to balance the aberrations while keeping the engineering, lens quality, alignments, etc at reasonable cost and effort.

I believe it is the small sensor that helps the camera achieve the zoom at that price. The P900 sensor is the same size as the Canon PowerShot A810. A 355mm full frame lens would achieve the look of 2000mm on the P900 sensor due to the crop factor. Since a full frame lens produces an image that fills more than the entire full frame sensor, a lot of costs can be reduced by creating a lens that produces a much smaller image.

My best guess as to what we're witnessing in these videos is some sort of manufacturing issue with the camera lens zoom. I've got a P900, and it feels kind of cheap compared to its DSLR big brothers. I'll toy around with it this week to see if I can cause the zoom and focus to malfunction.

 

[Mick West]

I've got a P900, and it feels kind of cheap compared to its DSLR big brothers. I'll toy around with it this week to see if I can cause the zoom and focus to malfunction.

I have a P900, and a circular polarizing filter. I get nothing when filming Venus. No sure what I could do to force it to happen.

 

[LilWabbit]

The effects of the earth's atmosphere on the telescopic image of Alpha Piscium from Edinburgh (more atmospheric effects) and from Alta Vista (less atmospheric effects), compared:



We know astronomical seeing/blurring is the blurring of astronomical objects (observed by telescopes) caused by earth's atmospheric turbulence and related optical refractive index variations (air density fluctuations). Considering the OP footage is taken horizontally or perhaps even subhorizontally from a plane flying in the tropopause, it's worth noting that atmospheric blurring (as well as dispersion) gets worse the lower you look (closer to the horizon) since you are looking through more air.



In the tropopause the atmospheric turbulence is:

Article:

Distant, rarefied, high velocity turbulence

Source: https://www.innovationsforesight.com/wp-content/uploads/2016/04/Astronomical-seeing-NEAIC-2016_FullVersion.pdf

In the lower atmosphere (boundary layer) the turbulence is:

Article:

Proximate, dense, low velocity turbulence

Source: https://www.innovationsforesight.com/wp-content/uploads/2016/04/Astronomical-seeing-NEAIC-2016_FullVersion.pdf

Atmospheric refractions can also be highly dynamic:

Article:

Astronomers often talk of seeing cells — air-eddy lenses, millimeters to meters across, that swarm through the sky. These eddies originate wherever air masses rub past each other — either horizontally in winds, vertically by convection, or both. Sometimes, when watching an extended object like the Moon or a planet, you can focus the telescope on a horizontal layer of "shear turbulence" a few thousand feet high. The ripples sharpen up when you turn the focuser slightly to the outside of infinity focus (moving the eyepiece farther from the objective). This is the signature of an inversion layer, in which a mass of warm air flows across cooler air below. The actual temperature difference may be very slight.

Large or slow-moving eddies cause slow seeing, but they don't stay large forever. No matter what size the eddies are when they originate, they break up into smaller and smaller ones. When these finally become small enough to measure in millimeters, they die out and dissipate their energy as heat via the air's fluid friction (viscosity).

Source: https://skyandtelescope.org/astronomy-equipment/beating-the-seeing/

Atmospheric blurring also renders a planet's refraction quite different from that of a star as illustratively explained in this video from 4:58 onwards. It has to do with the fact that a single atmospheric cell (or 'seeing cell', basically tiny little lenses swarming the atmosphere), due to proximity to observer, is optically larger than the star behind it, whereas with Venus many variously refracting air lenses 'cover' the object. Hence, the stars twinkle while the planets refract in a more complex way:

Source: https://www.youtube.com/watch?v=kqQ9rQ-VDdA

The movement of the plane is likely to compound each, (1) dynamic atmospheric refractions, (2) lens/window refractions, and possible (3) droplet-induced refractions affecting lenses and windows, creating the shape-shifting effect we see in the footage.

My two cents at this point (very much subject to revision).

 

[AmberRobot]

But the patterns shown in the video seem far more stable than I would expect from atmospheric seeing, which should constantly be changing due to the random nature of the turbulence that causes it. What is Shown looks far more like the way an image might change as you change the aberrations due to focus shifts or changes in field position.

I note that I have no experience with using that camera and looking at stars or planets so I will defer to the experience of those of you have. I am just stating what it *looks* like to me.

 

[Ravi]

I agree with @Amber Robot here.
Also seeing happens on a much faster timescale (ms range, not tenths of seconds).

The P900 clearly also has trouble focusing. A notorious problem with complex refractive zoom lenses is that the zoom makes the image (of a star) go out of focus, so it actively has to correct the focus element when zooming in. I am sure the algorithm used is based on real life imaging and not stars/point sources, so I can imagine the camera has problems.
I think this is seen in OP, in combination with the bad plane window.

 

[Mauro]

Could vibrations of the window panes have some responsibility too?

 

[Ravi]

Could vibrations of the window panes have some responsibility too?

I guess, but the effect seen in OP video is a rather slow effect.