Tunnel Vision – Step Into the “Ring”…


Who doesn’t recognize this awesome image of Messier Object 57 which was taken by the Hubble Space Telescope? The original color image was assembled from three black-and-white photos taken through different color filters with the Hubble’s Wide Field Planetary Camera 2. We know the blue filtration isolates emission from very hot helium, which is located primarily close to the hot central star… just as green represents the further away ionized oxygen and cool red shows ionized nitrogen gas at the farthest position of all. We know where they’re supposed to be, but we’ve never quite seen it in dimension until it’s been visualized by the “magic” of Jukka Metsavainio…

Like all our our “stereo” image produced for UT by Jukka Metsavainio, two versions are presented here. The one above is parallel vision – where you relax your eyes and when you are a certain distance from the monitor screen the two images will merge into one to produce a 3D version. I have heard from a friend recently that if you place a card in the center of the image with the edge towards you, it aids in seeing the parallel version. (And he was right.) The second – which appears below – is crossed vision. This is for those who have better success crossing their eyes to form a third, central image where the dimensional effect occurs. (The card “trick” also works well here, too!) Jukka’s visualizations of what Hubble images would look like if we were able to see them in dimension come from studying the object, its known field star distances and the different wavelengths of light. Are you ready to “cross” the boundary and step into the “Ring” for another round with Messier 57? Then let’s rock…

M57 Cross Vision by Jukka Metsavainio
M57 Cross Vision by Jukka Metsavainio

Originally discovered by discovered by Antoine Darquier de Pellepoix in January, 1779 and independently found by Charles Messier later that same month, it was Darquier who first said that it was “…as large as Jupiter and resembles a planet which is fading.” Thanks to his description, the term ” planetary nebula” stuck because of their similarity in appearance to giant planets when viewed through small optical telescopes. However, Sir William Herschel wasn’t quite so aperture limited, and he was the first to propose this new object was a nebula was formed by multiple faint stars. By 1800, Count Friedrich von Hahn had discovered M57’s central star and within 64 years William Huggins was studying its spectral signature. Just a blink of a cosmic eye later, another 22 years, Hungarian astronomer Jen? Gothard had discovered it had a planetary nebula nucleus.

What has remained constant over the years is the classic bipolar structure associated with the “Ring” nebula – a prolate spheroid with strong concentrations of material along its equator. Its symmetrical structure is one of the best known in the night sky – right down to the knots along the edges that can often be observed with larger telescopes. What exactly are they? According to C.R. O’Dell (et al); ” The equator of the Ring Nebula is optically thick and much denser than the optically thin poles. The inner halo surrounding NGC 6720 represents the pole-on projection of the AGB wind at high latitudes (circumpolar) directly ionized by the central star, whereas the outer, fainter, and circular halo is the projection of the recombining AGB wind at mean to low latitudes, shadowed by the main nebula. The spatio-kinematical properties of the Ring Nebula and the origin of the dense knots commonly observed in late-stage planetary nebulae are critically compared with the predictions of radiation-hydrodynamic and wind interaction models.”

These winds, bubbles and explosions were part of the original Hubble photograph where our visualization came from. “We have studied the closest bright planetary nebulae with the Hubble Space Telescope’s WFPC2 in order to characterize the dense knots already known to exist in NGC 7293.” says O’Dell, “We find knots in all of the objects, arguing that knots are common, simply not always observed because of distance. The knots appear to form early in the life cycle of the nebula, probably being formed by an instability mechanism operating at the nebula’s ionization front. As the front passes through the knots they are exposed to the photoionizing radiation field of the central star, causing them to be modified in their appearance. This would then explain as evolution the difference of appearance like the lacy filaments seen only in extinction in IC 4406 on the one extreme and the highly symmetric “cometary” knots seen in NGC 7293. The intermediate form knots seen in NGC 2392, NGC 6720, and NGC 6853 would then represent intermediate phases of this evolution.”

Anyone who is willing to step into the ring with this champion of all planetary nebulae is liable to end up with a few knots somewhere! Enjoy your tunnel vision journey….

21 Replies to “Tunnel Vision – Step Into the “Ring”…”

  1. This is easy to see too.
    I’d like to add that an old Indian astronomer, Jayant Narlikar, in his book ” The 7 wonders of the Universe ” says that we call these nebulae planetary nebulae becouse they are lighting up from their star, like the planets of the solar system.
    Also, he calls these objects ” smoking guns “.

  2. I didn’t know you could do it by crossing your eyes. I was able to do both ways. What was weird about the crossed eye method is that the image appeared much smaller.

  3. It is images like this that makes me really wish that Star Trek was real. I wonder what this would look like from the inside. Would it fade away as fogs do when you approach, or would the sky be filled with this beautiful object? If I were captain of the Enterprise I would likely be relieved of command. I would be too tempted to go sighseeing at objects like this one.

  4. Often, if this type of image is produced wheres image centers are further apart than your own eyes, you will not be able to see the image in 3-D. Eyes really don’t focus beyond ‘straight out’.

    So, on my Mac, I simply right-clicked to save the image to ‘Downloads’, and then opened it (double-clicking) in Preview. Does this automatically. Then just click the “-” button near the top and it reduces the image by about 20%. That’s enough so that when relaxed, the eyes CAN see the 3-D image. Reduce the image one more click if you have trouble ‘relaxing’ your eyes that much.

  5. Marco says:
    “If I were captain of the Enterprise I would likely be relieved of command. I would be too tempted to go sighseeing at objects like this one.”

    Same here, I reckon, but would I care? I have a fast starship – let them try and catch me…. πŸ˜‰

    btw: I don’t seem to be able to “get” the parallel vision images. The cross-eye versions look stunning, though!

  6. i have the most trouble with parallel – but i found out that if i make the image so that it’s only taking up about 2/3 of my monitor screen that the “card trick” works. (for example, i can place my mouse pad edge on in the center of the image and it somehow tricks my brain into focusing it better.)

    no matter what size, i fall right into the cross vision. the larger the image, the further i have to be away from the monitor. now… here’s the kicker. i found out that i can even print these images at real low rez on a real cheap color printer (for example, a single square is only a couple of inches in size) and it will work. it’s not as glamorous and colorful as when lit on the screen – but it works.

    and yeah, dudes… i got the impression when i looked into it that you could fly right into the tube… wait until you see the one where you’re looking at a planetary from another angle! maybe next week? πŸ˜‰

    for those of you who really enjoy these images, there’s a very special project coming up where i could use some volunteer eyes and your honest opinions. please feel free to write me at theastronomer2 at gmail dot com and i’ll fill you in on the details.

    until then? don’t be afraid to cross your eyes and fire up the warp drive… because you’re really gonna’ love some of the places the future will take us!

  7. I don’t know how many people have sent me an email saying that Messier Object 57 is officially referred to by NASA as “THE EYE OF GOD”. In reality, NASA only refers to the object as either the Cat’s Eye Nebula or Messier Object 57. I don’t think NASA has ever referred to that object as “THE EYE OF GOD”.

  8. Every one of these 3D pics I have looked at are fantastic! I agree with Marco, wish I could be in the Enterprise and explore this nebula. Is the star in the very center the one that exploded? Breathtaking, gorgeous, amazing… I love these!

  9. I don’t get this. From the top image I see a tunnel, with the orange ring coming towards me. With the second image I see the center bulging out towards me with the orange ring looking lid a “flat” disk in the background.

  10. Definitely cool. The easiest way I’ve found of looking at the parallel pair is to focus each eye through a cardboard toilet paper tube or paper towel tube, holding them like binoculars. I fine it easier to focus my eyes when the tubes screen out the surrounding text.
    Thanks, keep them coming …

  11. I have no trouble viewing either relaxed or crossed versions. I start with slightly crossed eyes (not too painful) then a few quick blinks and relax (uncross till its not painful) and the image pops right out.
    I did notice something odd though.. the top (relaxed) view looks layered front to back (blue stands out, followed by white, then yellow and finally red). The bottom (crossed view is oppositely layered front to back (red, yellow, white, then blue). Anyone else see this? If not, it’s off to my optometrist.

  12. I noticed something odd too, the top version tends to want to come ‘out’ towards you, and the bottom version goes ‘away’ from you like it is suppose to be. Maybe has to do with something about what Will said.
    Might seem like a dumb question, but I don’t know…. is the star in the center the one that exploded?

  13. Hi 3rd Rock,
    I blew the image way up and did see that the center object looks to be the brightest however; the object to the right looks a bit dimmer and it seems to be a double object (bright top and dimmer bottom) and both this and the center object have the lensing spikes.
    In line with my comment r.e. the “Fermi Glimpses”, is it possible that two back to back SN/GRB events in close proximity, result in a smooth symmetrical nebula such as this one? In this case, the one kicked off to the right was the lower energy “baby” event?
    Still fishin w/o bait. lol

  14. I had a lot of difficulty with that one. I had to chop the black out of the middle to get the images closer together so that they would merge for me.

    I think it is the high contrast between the rings and space that causes my eyes to want to look at the rings instead.

  15. Does anyone else see the face of a dark baby in the middle? Way too “2001” (which should have been in 3D).

  16. I see some people perceive a “dome” rather than a “tunnel”.

    I did a little test: I swapped the (cross-eye) images around in an image editor – expecting the effect to be either spoiled, or to see a dome instead of a tunnel…. but it still looks the same as before. This will demonstrate to those who know that I haven’t got a clue how this works at all, at all….

Comments are closed.