Does anyone know about this phenomenon? My friend Benson Farb, under the charming misimpression that I am some sort of astronomer, sent me the following image, taken by his uncle Henry Farkas, MD.
That’s the Moon on the right, somewhat overexposed. On the left is another image of the Moon — substantially dimmer. So what is going on?
Consulting the Google, I was able to find multiple examples of similar phenomena, but no explicit explanation: see here, here, here, here, here, here. My first guess was that we were glimpsing a giant Death Star that had been hiding behind the Moon, but upon further thought I regretfully concluded that it’s unlikely we would have alien invaders clever enough to build a Death Star but sloppy enough to reveal it prematurely like that.
Actually there is only one sensible explanation: some sort of lensing/reflection phenomenon that is giving rise to multiple images. The two obvious culprits would be the camera lens itself, or the atmosphere. But Henry took the picture in the first place because he saw the ghost image with his naked eyes, so the camera lens is out. Atmosphere it is! This is somewhat corroborated by the fact that different exposures show different separations between the images — something that could be explained by changing atmospheric conditions.
The atmosphere, whose layers can have very different humidity and temperature, can be a very effective reflector and refractor. Here is an image of a “sun pillar,” to show how dramatic the effects can be.
So I’m pretty convinced that the atmosphere is to blame. On the other hand, it’s a little funny that the images aren’t vertically aligned, which is what I would naively expect. And this wouldn’t be the first time that my lack of real-world knowledge steered me dramatically wrong. Anyone familiar with this phenomenon?
That’s no moon.
This has all the marks of an internal reflection of the lens system to me. Easy test (esp. since several pictures exist): Is the “ghost” always in a spot which is a point reflection of the Moon’s position relative to the center of the field of view? If so: case closed! Bonus: the top picture here shows such an internal reflection of a partially eclipsed Sun, which also highlights the geometry involved.
It can’t be an internal lens reflection if it’s seen with the naked eye.
What if the naked eye is looking at the moon through corrective lenses? Those could also introduce a similar reflection. I’ve noticed my glasses producing extra images of high contrast sources like the full moon against a dark sky.
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It appears as though Luna has been tidally locked by a red dwarf.
I suppose you could investigate some of the variables. Are the images of the ghost moon taken as the moon is coming up and/or going down versus directly overhead? Does the camera image accurately represent what the viewer sees with the naked eye, not wearing glasses?
“My first guess was that we were glimpsing a giant Death Star that had been hiding behind the Moon, but upon further thought I regretfully concluded that it’s unlikely we would have alien invaders clever enough to build a Death Star but sloppy enough to reveal it prematurely like that.”
Ah, but the Tarkin Doctrine emphasizes terror over utility. An early reveal to a victim with no hope in hell of stopping the thing would not be inconsistent. . . .
It would have helped to know the date, time, and location of the shot, as well as the weather conditions at the time, and the model of the camera. The three .jpg images aren’t even of the same size, in pixels (download the images and check the files!). Eyewitness account of the same phenomenon being seen without the camera notwithstanding, I lean heavily to the in-camera explanation.
i saw that moon at 07:00 yesterday morning .it was a very clear morning with full moon .I said to the wife we got two moons very weird.
I think this could be caused by a thin, sharply-defined layer of mist/cloud (or just possibly dust?). The second moon is the illumination of this layer.
In principle the image would appear directly between the observer and the moon. However the most likely cause of such a layer would be the interaction of two layers of air: one cold and the other warm and moist. In this case the different densities of the two layers could cause the image to be refracted away from its nominal position.
What I don’t understand though is why the ghost moon is smaller than the moon.
You sure it wasn’t taken through a glass window. Multiple reflections in the glass will do it. Normally you can’t see them unless there is a lot of contrast like the full Moon in a dark sky.
I’m the guy who took the photos. I was outside, not looking through a window, and I wasn’t reading, so I wasn’t wearing my reading glasses. When I saw the image with my eyes, the ghost image was partly overlapping the actual moon image and was at an angle to it. The images were taken only a second or so apart because I have my camera set to take three images every time I press the shutter release, or whatever they call it these days with digital cameras. The first image is taken at whatever exposure the camera’s computer thinks is correct. The second image is 2/3 of an f stop darker, and the third is 2/3 of an f/stop lighter than the camera’s computer thinks is correct. The camera was oriented horizontally just the way the photos are displayed above. The top image is cropped a bit and darkened a bit to get rid of the surrounding glow, but the other two images are not edited at all.
Henry
On October 25th, 2010 at 12:03 pm, Jonathan Lubin asked for some information about the details of the camera. Here they are:
The camera is a Canon PowerShot SX 10 IS superzoom.
The focal length was zoomed to 100mm. This is the 35mm equivalent of a zoom to 589mm. It was hand held so clearly the image stabilization kicked in.
The photos were taken on Oct 21st, 2010. The weather was severe clear.
The first one registered at 9:07:03pm. The shutter speed was 1/20th of a second and the aperture was f/5.7. This first shot was the one where the ghost image is touching the real image.
The second image registered at 9:07:04pm and the third, the one I cropped, registered at 9:07:05pm. Although I thought I had the camera set to record a regular image, a darker image, and a lighter image, all three images, now that I look at the metadata, had the same shutter speed and aperture as the first image.
I have to reiterate, there was no glass of any kind between me and the moon when I saw the ghost image. There is one detail that I should mention. Cameras don’t see as well as eyes do. To my eyes, the ghost image did look like it was exactly the same size as the actual moon. It was just not anywhere near as bright as the actual moon. You have to remember that my camera isn’t all that high quality. It’s a point and shoot with a zoom lens.
Henry
Looks like what was left of The Great Evil after Milla Jovovich got done with it.
But Seriously – Dr Farkas – what was your latitude when this was taken?
Also, have you ever had radial keratotomy or other surgery to correct your vision?
@Henry: Did you do the test I proposed in comment #2 already? Must be done on uncropped versions, of course, i.e. you have to know the center of the FOV precisely. Given a sufficiently bright light source (the Moon would still do it tonite) and identical or similar camera settings, the effect should also reappear. The non-Moon-ly color of the reflection is caused by lens coatings, by the way; this topic comes up on astronomy web sites quite frequently.
Now regarding your visual impression: How long it did last and was that “ghost” changing its distance and/or angle from the Moon while you saw it? My hypothesis predicts that it didn’t, as in my view what you saw was a different (physiological) phenomenon in your eye(s) – where a lot of optical ‘elements’ are present that can scatter light into glare effects in an asymmetric fashion – which would follow different geometrical rules than the internal lens reflection.
Just some thoughts from a seasoned amateur astronomer who has seen lots of visual as well as photographic artefacts over 30 years …
I’ve seen identical images many times in pictures I’ve taken that were never visible with the eyeballs. The separation from the moon can be changed by positioning of the moon in the field of view (always symmetric about the middle). Different degrees of brightness and colors is possible (I was once fooled into thinking I discovered a comet by a green reflection from a bright star), and changing lenses can change that. I always photoshop it out. So basically, it can be caused by the camera optics. Claiming it’s visible to the eye is just an anecdote 😛
Check the pictures and see if the reflection is symmetric with the moon. If so, what’s in the pictures is an internal reflection. Which doesn’t mean that he didn’t see anything with his eyeballs, but whatever he saw would not be the same thing as what’s in the pictures.
Check out http://www.theflatearthsociety.org/forum/index.php?topic=43522.0
for the Flat Earth Society take on this.
Perhaps it’s the Anti-Moon/Shadow object theorized to cause eclipses in Flat Earth theory?
I was in the parking lot outside my brother’s condo. According to iTouchMap.com, I was at
Latitude, Longitude
39.363969,-76.468644 Just east of Baltimore city.
I can’t duplicate the photo with my camera tonight. It’s cloudy outside. But I have to tell you, I take photos of the moon every so often just to see how steady I can hold my camera (ah, the glories of digital photography, where you can take pictures for free) and I’ve never seen this happen with my camera before. I’m not sure what test I’m supposed to do about that FOV (field of view?) thing that was mentioned in response #2.
Jason A says that if it’s an internal reflection, the ghost image and the moon will be symmetric with the center of the image. You can’t tell with the cropped image, but the other two images are not edited at all, and the ghost image is not symmetrical with the actual image around the center of the photo.
When I was seeing the double image with my eyes, the ghost image wasn’t anywhere near separated from the real image. There was around a fifty percent overlap. And it wasn’t moving. I originally thought my eyes weren’t working together. That’s why I took the photo. Seeing double is definitely not recommended by the eye doctors or the neurologists. Vertical or diagonal diplopia (double vision) is a very bad sign.
When I take photos with my camera, just like with a single lens reflex, you can’t see the image you’re photographing while the image is being captured. It’s not as if my camera has a mirror that flips up like in the SLRs. The camera company, Canon, could just as easily allow me to continue seeing the image as it’s being captured. They just don’t. This is a bit problematic when you’re capturing three images in a row since it’s difficult to keep the camera precisely aimed when you can’t see what you’re aiming at for two whole seconds. That’s why the image of the actual moon isn’t in the same spot in the two uncropped photos.
Henry
The internet source for this stuff is a website called Atmospheric Optics (http://www.atoptics.co.uk/), check through the site for all manner of strange things our atmosphere can do. If you can’t find the answer, send in the pic for a diagnosis, Les loves to collect pics of different phenomena.
The only thing I can think of that can explain this is that it’s the moon illuminating a small circular / spherical cloud perhaps of reddish particles. This explains the smaller size, the red coloring, and the fact that it is moving.
Ice crystal phenomena typically have a preferred angle. For example, we’ve all seen sun dogs and moon halos.
By the way, my understanding is that a sun pillar is due to ice crystals aligned by gravity causing reflection / refraction rather than by refraction due to air density alone. I’ve only seen them in the presence of high (i.e. icy cold) clouds.
@Sean (comment 3): In none of his comments Henry has confirmed that the thing he saw behaved in any way as the thing on the photographs, namely changing its relative position by several lunar radii within seconds. This is a giveaway that what he saw (eye glare from the bright Moon as the “weather was severe clear”) and photographed (lens flare, frequent in point & shoot cameras) is unrelated. Henry also stresses (comment 14) that the visual ghost moon had the same diameter as the real Moon and was – apparently constantly? – offset by 1/2 diameter. Which is not the case in any of the 3 photographs by a large margin. Finally regarding the idea (Sean’s original post) that atmospherics optics might be involved: I’ve attended a number of conferences on this topic, covering both frequent and rare phenomena – there simply isn’t one that involves a 2nd image of a bright object jumping around in its vicinity, let alone when the sky is clear.
Ah, here we go. A little google-fu shows that this is a problem for amateur astronomers. Basic light pollution problem with clouds:
“Faint stars disappear, only the Moon and the brightest planets stars remain visible. If the night is cloudy, the light pollution effects are striking. The clouds are red and bright and one could read the newspaper using the light reflected by the clouds. So much light is uselessly pumped toward the skies that the reflected light is enough for a decent illumination. I’m fairly sure that was not the intention here… The waste is enormous. At a fraction of the cost, we could have good design lamps with lower power which can provide the same illumination.”
@Carl: Look at the exposure times and f numbers Henry gave in comment #14 – the (as I explained non-)phenomenon is orders of magnitude brighter than any light pollution-lit cloud could ever be (and there were no clouds anyway, as he said). Apparently “google-fu” doesn’t replace actual sky observing experience …
The last two images shown above were taken only a second apart?
Surely it can’t be an atmospheric phenomenon then – it would require
high altitude clouds to be moving in pretty spectacular ways to shift
the image like that. And coherently too!
It’s gotta be a near field effect. If not the camera optics, then some sort
of ground layer fog, although I believe the weather was claimed to be clear. Could the temperature have been hovering around the dew point?