APOD: A Triple Sunrise Over Gdansk Bay (2009 Aug 04)

[alaf]

Much as I agree that the more common cause of such an effect would be the multiple window panes, I am firmly on the side of atmospheric refraction in this case. As pointed out by some previous writers, the clouds interrupt the second and third images in a pattern consistent with interposition between the images and the viewer; one must conclude that the refraction occurred distant to the clouds.

[geckzilla]

Much as I agree that the more common cause of such an effect would be the multiple window panes, I am firmly on the side of atmospheric refraction in this case. As pointed out by some previous writers, the clouds interrupt the second and third images in a pattern consistent with interposition between the images and the viewer; one must conclude that the refraction occurred distant to the clouds.

Again, I ask, can you actually see the whole cloud pattern in front of the original sun? How can so many people make the assumption that the cloud pattern in front of the reflected suns is different from the first generation since the light is so bright it is impossible to see?

[annie1931]

In my very humble opinion, it looks as though there were two causes - one, the effect of double glazing (ruins most of my sunrise/sunset pics), and a mirage-like effect of nature some how, thus creating the three images. Fascinating pic, regardless!

[Mad Platypus]

Thanks to everybody for a great scientific debate! geckzilla's last post finally won me to the window pane, especially since several of the pictures look exactly like the APOD. All that's left is for RJN to contact the photographer and ask about the window.

[Tommy Boy]

I would have to say the reason for the illusion of a triple sun could very well be a third party object not seen,
Camera lens and internals aside the photographer could be wearing cheep glasses with the polycarbonate frame, I had a pair once and I had light shadows and mirror images all the time.
Just my thoughts.


Tom.

[green1]

["It was rising above Lake Superior through the window behind me. I was surprised to see two suns, one on top of the other... I went across to the cafe’s terrace entrance and pushed the door open ... Sure enough, with nothing but our atmosphere between me and Sol, the image remained the same.
I assumed the cause to be a refraction caused by the thermal layers above Lake Superior and the city of Duluth, below the campus, along the water’s edge. There are many strange phenomenon that occur when the mercury dips so low."]

My earlier post also mentions water reflection in the instance of double rainbows (vertical images). Rschmit brings up another possibility of varied refraction through colder (i.e.: denser) air to the north. A strong cold front off the arctic circle (remember the latitude of Gdansk) might also be responsible for a lensing effect which could result in multiple images. I again point out that the cloud shadow in front of the reflections is different than that of the primary. In fact if a curved line is drawn at the top of the shadows (think "sine wave") it shows a continuous contour consistent with a single bank of clouds, showing that the reflected light is behind the clouds rather than in the windowpane.

cloud contours

triplesunrise_diacon lines.jpg (32.42 KiB) Viewed 3591 times

[bystander]

On the far left of photo 9802. The concrete wall. Is this discoloration of the concrete or reflection on a pane of glass? I'm leaning towards reflection. It has to be a window creating the effect.

I don't think it is a concrete wall. I think it is a curtain or drapes. Looks more like cloth than concrete.

[ExNihilo]

Much as I agree that the more common cause of such an effect would be the multiple window panes, I am firmly on the side of atmospheric refraction in this case. As pointed out by some previous writers, the clouds interrupt the second and third images in a pattern consistent with interposition between the images and the viewer; one must conclude that the refraction occurred distant to the clouds.

Again, I ask, can you actually see the whole cloud pattern in front of the original sun? How can so many people make the assumption that the cloud pattern in front of the reflected suns is different from the first generation since the light is so bright it is impossible to see?

Good point, and I have to agree it applies perfectly to the primary image. However, comparing the 2nd image to the much weaker 3rd image, it looks like the percentage of obscuration by clouds of the 3rd image is somewhat greater than the 2nd image. Not something you'd expect from just a window effect.

[dawg64]

As a boy in the 1950's I remember going to a barber shop that had mirrors along two walls that faced each other. As I sat in either the waiting chair or the barber's chair, I marveled that I could see my image reflected countless times in the mirrors. It seems possible that the rising sunlight may have been reflected from some of the low-lying clouds back to another layer of clouds which created the image of the second sun. Some of that light may have been reflected again to a third layer of clouds which created the third and faintest image. Perhaps most of the reflected light by the faintest image was lost due to decreased reflectivity of that cloud layer. In any event the picture is quite impressive.

Dorsey Yawn
Tampa, FL, USA

[opt1cs98]

Looks like there's another image of the sun...but I think this one is caused by the lens system.

[geckzilla]

• The clouds are impossible to outline. Not only due to the nature of clouds not having hard outlines but also because the sun's brightness and the camera's exposure obscures them beyond the point where one could determine the location of the clouds within a reasonable degree of accuracy.
• The color and value of the sky and clouds and the color of the sun's reflection match very closely and can appear to blend into one another.
• There is not a lot of dynamic range in the values near the sun. It goes from very bright to moderately dark very quickly.

That's it, I think that's enough evidence. The sky and cloud color is very close or exactly the same to the colors that are reflected onto the window by the clouds that are in front of the sun. Think about that. It's an illusion that the reflection of the sun is behind any clouds. Your mind is making an assumption that what you see is a cloud when in fact it is not. The clouds all being horizontal and congruent assists you in this assumption. Only the parts of the reflection that are bright enough to be seen are being seen, so the parts darkened by the clouds get overlaid onto the background. It just so happens that the background clouds overlap in a way that makes it look like the reflection is behind them.

I'm assuming there is a multi-paned window of some sort in front of the viewer and has been observed and documented reflecting the sun in this manner many times. The other assumption seems to involve some fantastic phenomenon involving vertical columns of air which has never before been observed and cannot be explained. I'm sticking with my window, dammit!

ps - sorry I edit my posts so much. I try to get it right the first time but it doesn't always happen.

[clempi]

Hello all,

I am new to this board, intrigued by the triple sunrise APOD. I would not enter the technical details to explain it but I have one (logical) remark about the picture:
Gdansk being in the northern hemisphere the sun should rise from left to right but the photo gives the impression that its reflections went from right to left. Assuming that the brightest sun is the actual one and no reflection, how could this be? My answer would be that we look at a sun going down, thus the information of a 4h30 shot cannot stand.

With all due respect I doubt the given information, if it weren't that the photograph had been flipped horizontally. But then why is this not mentioned?

I would be thankful for any explanation, cheers

[Wayne]

Those of you analysing cloud formations are completely ignoring that the window reflections are superimposed atop of the distant clouds. So of course you will see clouds through them and, the reflection being transparent, it will appear to be "behind" clouds.

[Chris Peterson]

Again, I ask, can you actually see the whole cloud pattern in front of the original sun? How can so many people make the assumption that the cloud pattern in front of the reflected suns is different from the first generation since the light is so bright it is impossible to see?

The primary solar image is very nearly saturated, although not quite. From what can be seen of the clouds in front of the disc, as well as where the clouds cross the limb, it appears to me that the cloud patterns on both the secondary and tertiary image are a perfect match. Add to that the match between the lower distortion on the two brighter images, and there's really no doubt at all we're seeing a foreground reflection of some kind.

Of course, there's also the little problem that no atmospheric phenomenon could produce three discrete, undistorted images like this.

[polymath]

Refringence, in this case trirefringence, might explain the triple images. The causes of this particular image phenomena might include curvature of and the distance sunlight traveled through Earth's atmosphere, atmospheric conditions, relative position of observer. Refringence is the decomposition of a ray of light into more than one distinct ray. Commonly observed, birefringence of relatively nearby objects seen through optically, directionally-oriented transparent material produces two images. Directionality is dependent on the orientation of the optical axis(es) of the refringing medium.

[geckzilla]

Chris, they do match quite well. I tried lining them up using Photoshop but there's plenty of distortions and places where I'm not sure whether I'm seeing a part of the reflection or a cloud behind it so I didn't post it. I then tried outlining what I knew were clouds, what I thought were clouds, where I thought the sky was, and where I knew the sun was and came again to the same conclusion that it's an illusion in more ways than one.

[BikerMike]

It would appear to me from the angle that the adjoining balcony is viewed and the concrete wall that can be seen in the left of http://apod.nasa.gov/image/0908/IMG_9802.JPG that Noemi is standing inside the building taking the photos at an oblique angle (As Heiko, guessing close to 45 degrees.) to the plane of where the window glass would normally be.

I suspect that the reflections Heiko (MadCat-75) makes note of are probably of something inside the room.

I started to look into Exposure Values as I noticed that the photo exposure value keeps increasing even though the focal length is increasing. I believe that for the same light conditions the exposure value should decrease with increasing focal length. But then decided that it was a bit of a can of worms as we don't know the settings on Noemi's camera.

Would like to know if Noemi moved at all between any of the exposures.

My money is on a window causing the phenomenon.

Cheers & Beers!

[MadCat-75]

Hi,

there are clouds also befor the original sun - but the ccd is overdriven. The center of the sun is #FFFFFF, which is pure white.
There are clouds, but not visible in the foto. Only on the faint second sun, there are they visible.
So there are no clouds in the foreground of the second sun, because this actually the clouds from the original sun wich are mirrored too.

See ya,

Heiko

[orin stepanek]

It may turn out to be a window reflection; but than why aren't we seeing ghost images of the tower and distant buildings? I wonder too why we wouldn't see some reflections from inside the room? I've seen setting suns have double images at times; usually one dissolves after a while; but one was always the duplicate of the other. One was always directly above the other rather than side by side. I never experienced a view over a body of water however.

Orin

[Jay]

I viewed the images posted by RJN and the time stamps were not visible in them.

However, if the orientation with time stamp is the same as that presented in the APOD posted images, i.e., offshore platform to the left of center in image, internal window pane reflections or multiple window pane relections MUST appear to the right of the brightest sun image, given the angle of the building in the brightened mages, unless the the window being looked through is a projected window (unlikely considering the balcony construction).

It would be interesting to see satellite photos of the cloud patterns of that morningover Gdansk baytogether with weather observational data.

I cast my lot with those supporting natural phenomena as the cause.

[napewastewin]

I once worked on the Pine Ridge reservation in South Dakota. Such "optical illusions" as this were frequent occurances there, and were called "sundogs". I've also seen sundogs at sunset, on the Oregon coast.

Sarah

[Chris Peterson]

It may turn out to be a window reflection; but than why aren't we seeing ghost images of the tower and distant buildings? I wonder too why we wouldn't see some reflections from inside the room?

Fresnel reflections from glass are about 4%. Each reflected image should be about 1/600 as bright as the previous. The Sun is the only thing in the image even close to bright enough to cause reflections above the camera's noise floor.

I see what appears to me to be reflections from inside the room.

[Chris Peterson]

I once worked on the Pine Ridge reservation in South Dakota. Such "optical illusions" as this were frequent occurances there, and were called "sundogs". I've also seen sundogs at sunset, on the Oregon coast.

Sundogs are halo effects, and can't occur less than 22° from the sides of the Sun. The secondary images seen in these photos are definitely not sundogs.

[DaveB]

Hi All,

As the two left most suns clearly have different clouds in front of them I cannot see that it is possible for the effect to have been caused by glass close to the camera.

I would sugggest that the presence of a body of water reflecting the sun into an inversion or similar atmospheric discontinuity is the cause of the multiple images. I have seen distant Great Barrier Reef islands refracted to be "floating" about 3 degrees above the horizion when they are geometrically below the horizion, I can see no reason why the suns reflection from water could not do the same in ideal conditions. The sea looks fairly flat in the images.

DaveB, Weather Observer, Cairns, Queensland, Australia.

[dockwatcher]

The reflection is 10% smaller. Does that rule out plate glass?
I can't get a good measurement on the second reflection but I think it is less then 10% smaller then the previous.

There are clouds over head, clouds in front of the sun and it looks like clouds behind. Is there a ripple of moisture several hundred miles long?

I think I would have to give this to the photographer. the reflections seam fuzzier as they go out. If it was glass wouldn't they stay sharp?