Folks,
Plain and simple: It’s the window glass. I hope/think the images discussed below will set to rest all the objections to this explanation.
Anybody who thinks otherwise does not understand how the atmosphere works.
The atmosphere is stratified horizontally, with small vertical systematic variations in the index of refraction. Hence, displacement due to the atmosphere will be VERTICAL. The exceedingly long path traversed by the setting/rising sun results in a maximum displacement on the order of a degree (twice the size of the sun). As noted by some other commentators, this refraction also elongates and smears our view of the sun (as can be seen in the image in question at the bottom of the sun).
Any horizontal variations in the index of refraction of the atmosphere will be way too small to cause more than very tiny lateral shifts in the apparent position of the sun - certainly nothing like degrees or more as seen here (bigger than the common, well-known vertical effect!). Additionally, as noted by others (and as seen in the solar images here and elsewhere), such shifts would tend to smear out the solar image. The crisp lateral displacements noted here would not occur without both a large change in the index of refraction and a discrete boundary in the atmosphere - larger than could possibly occur.
Optical astronomers worry all the time about the vertical dispersion of the atmosphere - it affects the spectra of stars taken at low elevation (where “low” here means tens of degrees of elevation). They NEVER worry about lateral (horizontal) dispersion - IT JUST DOESN’T HAPPEN!
Contrary to some comments, there will be NO effects due to the latitude of the observation. As noted above, the atmosphere is ->locally<- horizontally stratified.
Many of the objections to the dual-pane window theory seem to involve the sided-ness of the images, the curvature (mis-alignment) of the images, and the spacing of the images. The argument being that the spacing between the glass would have to be highly variable in order for these effects to be due to the glass. (The other primary objection seems to be the appearance of the clouds in front of the sun. This has been settled by the Photoshop overlays which show identical clouds, with the realization that the “primary” image is overexposed/saturated.)
Well, it turns out, even fine (?!) American glass is pretty crappy in this regard.
As the full moon was rising Wednesday evening in Flagstaff, Arizona, I took some pictures through one of our double-pane windows. All the effects that “can’t possibly be due to the glass” are, in fact, quite obviously seen here.
These four pictures were taken within a few seconds of each other, with my Pentax K20D digital SLR camera. The exposures are 1/13 or 1/10 of a second, at f/2.8. Autofocus, and image stabilization were turned on. I moved the camera 2 or 3 inches laterally between exposures, going from left to right. (Unfortunately, there is a window screen between the window and my camera. The screen causes the up-down / left-right spreading of the lunar image - rather like a very low dispersion diffraction grating. The screen, however, IS NOT the cause of the multiple lunar images.) The exposures have been highly stretched in Photoshop to bring out the third image of the moon. The overexposed lunar image is the brightest thing in the frames. That the overexposed moon is always in the same sky position can be checked by comparing it to the faint house lights seen below the moon in each image. Note, also, the frame of the tilted window and how it moves across the field of view as I move my camera. (The vertical striations in some images are an artifact of the camera image processing (I’ve seen this before for this camera for longish exposures)). The window was angled about 45 degrees (i.e. swung open) with respect to the line of sight to the moon.
In frame 1 (
http://astrodave.us/frame1.jpg) with my camera about as far to the left as I could hold it and still see the lunar images, the reflected images of the moon are to the LEFT of the primary image. The faint third image is almost obscured by the window frame. The images are not equally spaced, and they are not in a line.
In frame 2 (
http://astrodave.us/frame2.jpg), I have moved my camera a few inches to the right. The lunar images are not too far from being equally spaced, and the third (left-most) image has moved in relatively closer to the second image.
In frame 3 (
http://astrodave.us/frame3.jpg). I have moved the camera another few inches to the right. The ghost images have shifted to the RIGHT of the primary lunar image, indicating a significant change in the (lack of) parallelism between the two panes of glass which comprise this particular double-pane window. (This is a high-quality, modern (about 6 years old) american-made window. I have noted similar effects in other windows in our house, as well as other windows here in Flagstaff. It seems that exceedingly small variations in the relative orientation of the two panes of glass can have VERY large effects on the reflected images - as some of the other commentators here have been trying to say. It is time for the naysayers to give up on this point!) Note that here, the third image is very far away from the second image. Again, very minor glass misalignments can cause very large variations in the relative location and orientation of the reflected images. Note, too, that the second image is above the line between the primary and third image. Lack of linear alignment is another artifact of how the glass panes are oriented.
Finally, in frame 4 (
http://astrodave.us/frame4.jpg), with the camera moved yet another couple of inches to the right, it seems that the third image has moved so far from the primary image that it is either “behind” the right-hand window frame or completely out of the picture.
These pictures should put to rest all the objections about multiple reflections due to multi-pane glass. Variations in both the thickness of the glass and the relative alignment of the panes of glass can have large effects on the relative displacement and orientation of the multiple reflected images which occur as light bounces around between the panes.
You can all observe this for yourselves. The sun is generally too bright for such observations - except at sunrise and sunset! However, as shown here, the moon works well. I could easily see a double moon image with my unaided eye and it was obvious that the relative location of the second image moved wildly as I scanned my eye back and forth, and up and down with respect to my double-paned windows.
THERE IS NO DOUBT THAT THIS IS A WINDOW EFFECT. Those who think otherwise need to show us an observational counterexample, and produce a scientifically reasonable theory - no bogus appeals to never-previously-observed horizontal variations in the index of refraction, birefringence, over-the-horizon ice crystals, polar temperature gradients, etc. As shown by me and others, it is trivial to produce double-pane window glass examples which essentially duplicate all the features of the triple sun picture.
David B. Shaffer (Ph.D. Astronomy (Caltech) and semi-pro photographer)
PS This is my first post to this forum. I hope all the formatting and image URLs work OK. I felt compelled to respond because of all the atmospheric refraction nonsense being tossed around.