Look Into the Cat’s Eye…

Article Updated: 24 Dec , 2015


Are you ready for more stereo vision? This haunting Hubble Telescope image has been visualized for dimension by the one and only Jukka Metsavainio and gives us a look at one of the most complex planetary nebulae ever photographed. Inside NGC 6543 – nicknamed the “Cat’s Eye Nebula” – the Hubble has revealed delicate structures including concentric gas shells, jets of high-speed gas, and unusual shock-induced knots of gas… and thanks to Jukka’s “magic vision” we’re able to take a look into the Cat’s Eye as it might appear in dimension. Step inside and let’s learn more…

When Jukka produces an image, it’s more than just a clever Photoshop “trick”. Hours of study must go into each image, because the light is acting differently in each part of the nebula. To make these images work correctly, Jukka must understand which stars are causing the ionization, which stars are nearer and further from our point of perspective and so on. Each type of image is totally unique and what makes dimension work for a reflection nebula won’t work for an emission nebula. Says Jukka; “To be able to make those stereo pairs, one have to learn lots of things about the targets, and beside that, study the actual image more deeply than usual. Star distances must be measured by the size and the color. For example, stars with yellowish hue must be in or behind the nebulosity, white/blue ones are front of it.”

Because dimension will appear reversed by the method you choose to use to view these images, Jukka makes two versions. The first you see at the top of the page 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. 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. So, now that you understand the images are a visualization and how they are created, let’s take a parallel look…

NGC 6543 Cross - Jukka Metsavainio

NGC 6543 Cross - Jukka Metsavainio

And now it’s my turn to add a little “magic” to what you see.

Estimated to be 1,000 years old, the Cat’s Eye is a portrait of a dying star – and quite possibly an unresolved double-star system. According to research, the dynamical effects of two stars orbiting one could very well be the cause of the complicated and intricate structures revealed here – structures normally not seen in planetary nebulae. When NGC 6543 was first observed spectroscopically, it showed the presence of emission lines, an indicator of multiple stars, but also an indictor of diffuse gas clouds.

As studies progressed, more hypothesis about the NGC 6543’s structure began to emerge. Perhaps a fast stellar wind from the central star created the elongated shell… It could be the companion star is emitting high-speed jets of gas that lie at right angles to the equatorial ring… Maybe the stellar wind has carved out the inner structure of the nebula are there are more than one there? Says L.F. Miranda; “The velocity field of NGC 6543 shows the existence of two concentric ellipsoidal shells in the nebula. The two shells likely represent the inner and outer surface layers of a geometrically ‘Thick Ellipsoid’ (TE) which constitutes the basic structure of NGC 6543.”

Even more research ensued, and with it came the twin jet theory and the ejection of materials spaced over intervals of time – like cosmic smoke rings being puffed off at perfect intervals. According to Bruce Balik; “Hubble archival images of NGC 6543 reveal a series of at least nine regularly spaced concentric circular rings that surround the famous nebular core, known as the Cat’s Eye Nebula. The rings are almost certainly spherical bubbles of periodic isotropic nuclear mass pulsations that preceded the formation of the core. Their ejection period is consistent with a suggestion that quasi-periodic shells are launched every few hundred years in dust-forming asymptotic giant branch (AGB) winds but not consonant with the predictions of extant models of core thermal pulses (~105 yr) and surface pulsations (~10 yr).”

To be sure, there are simply a lot of things that we don’t know or understand about the Cat’s Eye Nebula just yet. It is possible that magnetic activity somewhat similar to our own Sun’s sunspot cycle, could be at work here. Says Dr. Balick; “What do the rings imply? Since they’re larger than the bright cores of the nebulae that they surround, the rings are almost certainly material ejected episodically before the main and bright core of the nebula formed. This means that the start that ejected the nebulae first quivered and shivered and made these concentric rings. Then something big happened, and the density and mechanism for ejecting the mass changed abruptly. This is when the core of the nebula was formed, typically between 1000 and 2000 years ago. The rhythmic ringing of a dying star is expected as the last of its nuclear fuel is suddenly triggered into ignition by the increasing crush of gravity — much like the juice ejected by squeezing an orange with increasing force. Each expulsion of juice temporarily relieves the internal pressure inside the orange. Similarly, each ejection of mass temporarily stops the combustion of the final dregs of the star’s remaining fuel. Why should the pattern of ejection mass change so radically and strongly? We can only conjecture. Its possible that an orbiting star or giant planet falls onto the dying star. It hits the surface with such force that its atoms ignite in a large conflagration. Somehow, the burst of heat drives the remnants of the dying star into space in fantastic patterns.”

And we looked right into its eye…

My many thanks once again to Jukka Metsavainio of Northern Galactic for his artistry and we look forward to the next installment!

32 Responses

  1. Sofia says:

    I’m cleaning my glasses…

  2. Thad says:

    I really enjoy this series of stunning stereo images by Jukka Metsavainio. Please keep ’em comin’ Tammy!

  3. Astrofiend says:

    Man these things rock my socks.

  4. robbi says:


  5. Freiddie says:

    I really like these kind of stereo images than the “blue-red” kinds.

  6. Freiddie says:

    Correction: I really like these kind of stereo images *more* than the “blue-red” kinds.

  7. Salacious B. Crumb says:

    The axis of the bipolar flow of the planetary nebula doesn’t look quite right to me. It doesn’t seem to match the velocity measures made of various features within the nebulosity, nor the calculated about 32 degrees to the line of sight. With blunt criticism, Jukka Metsavainio might just like to check a few paper on the morphology of planetary nebula (G.Pascoli work of 1999 comes to mind.), to make sure the stereo images show what has already been derived.
    Nice pic though.

  8. OilIsMastery says:

    You can really see the magnetic field lines quite vividly.

    Only electricity can generate magnetic fields.

  9. Chris says:

    I know how to shift my focus, but I’m having trouble getting them to come together. They seem too far apart to begin with, or else my eyes don’t have enough range of motion. Is anyone else having this problem? Any suggestions?

  10. Henry Solberg says:

    But it hurts way more to cross your eyes. I find looking further out greatly preferable.

    If you can’t do it, my (completely unfounded) advice is to simply let your eyes go unfocused. Since you are looking at a computer screen, “default” will definitely be further out. Having “learned” the muscles to use, you can then continue that motion as neccecary.

  11. Chip says:

    @ Chris: The second picture/pair is easier. You just have to cross your eyes on that one until the two images line up, then just focus them.

    Which makes me wonder why images like these in general are not set to “cross-eyed” 3D instead of “make your eyes spread apart” 3D.
    Trying to get your eyes to “relax” or look at some imagined point far beyond what you are actually looking at until your eyes line up with the images is pretty difficult for most people I know.
    Crossing your eyes is far easier and faster for everyone.

  12. Michael Booth says:

    It’s amazing to think that these SN remnants are cosmically speaking just like a puff of smoke after an explosion.
    The photo is just great!

  13. Vernon says:

    Once again, awesome. I have never seen the Cat’s Eye in that much detail, the rings really come out and are very impressive.

    With all my practice on the “Magic Eye” books, I have no problem crossing my eyes to make the third image appear. Took me all of three seconds to get the image.

    Please, please, keep it up, I would even suggest a whole book of these images, if possible with all the copyright rules.

    Thanks. Keep up the good work.

  14. Carl J. says:

    I’ve had at least 30 different people send me an email about the Cat’s Eye nebula, telling me that NASA oficially describes this nebula as the “EYE OF GOD”. Even though I do attend church on Sunday….. I think it’s absurd that all these conservative Neo-Con’s believe NASA oficially refers to NGC6543 as the Eye Of God.

  15. Frank P. says:

    Thank you much for the stereo images – they’re great. I convert some of them into (red/blue glasses) 3D images for my family that can’t cross their eyes to focus on the dual images.
    Keep it up!

  16. Rob says:

    Beautiful! Seeing this famous image in 3D for the first time gave me a new perspective on SNRs. I had previously imagined them in 3D, but this is, of course, not the same as “seeing” them in 3D. I’d like to see the object renamed the “Sea Shell Nebula”.

  17. HeadAroundU says:

    Doesn’t work for me and I don’t want to f*ck up my eyes. I gotta read a lot today.

    Why don’t you guys make a 3D video?

  18. gudenboink says:

    Speaking of the Hubble Ultra Deep Field picture – the last time I saw it profiled on the Science Channel they said it was a Million seconds of exposure time (I think) and talked about trying to get another Super Ultra Deep exposure of a million more or twice as long.
    (I HOPE! How COOL would THAT BE???)

    Has anyone heard anything about another extremely long or Super-Duper-Ultra-Ultra Deep Field?? The galaxies that were showing up in the UDF were fascinating because they were such goofy shapes AND were getting rather thinly spaced.

    I’m wondering if they would see much of anything else at twice the exposure – that would be REALLY close if not right up to the Big Bang – wouldn’t it?

  19. kymmie_cat says:

    What wonderful work by Jukka Metsavainio, a truly awesome pic. But only 1,000 years old … that seems like almost nothing in stellar time. A “dying” baby star?

  20. kymmie_cat says:

    The age of the star is based on many “ifs”. For those having trouble seeing the stereo image, Wikipedia shows a single image which you can enlarge and at least take in the beauty of it.

  21. Will says:

    It’s easier if you look straight on and not above or below your monitor. Also try saving image to desktop and using Windows picture and fax viewer or a like app to enlarge it. I find it easier to get it into focus and the bigger pic is better.

  22. Will says:

    While I’m posting, If it’s not breaking with protocol and if its not too much trouble, I would like to ask this question again. Ref. the 02/06/09 UT article “Deep Hubble View of Unusual “Fluffy” Galaxy and Beyond”. Sorry for my ignorance here…
    Q. why are the bg galaxies, esp. the circled/captioned ones, not “all” showing a strongly red shifted spectral signature which we should expect when viewing the distant and accelerating, young early universe? Some are red, some are white and some are blue. I asked this before when the famous HST deep field image was published 3 or 4 years back and didn’t get an answer.
    Is it because these HST images are composites taken with multiple filters and we’re seeing different chemical emission signatures. But then, it doesn’t seem reasonable that we should have individual galaxies made up of unique element(s). So confusing.

  23. hey, Will… if i’m around to read a question? i’ll find you an answer.


    Hubble Finds Hundreds Of Young Galaxies In Early Universe

    and see if that helps to answer some of your questions!

  24. Will says:

    Thank you Tammy,
    I recall reading this at the time and I also recall asking (who/where?) the same question. The one para. that touches on the image colors seems, to me, contradictory.

    “The galaxies unveiled by Hubble are smaller than today’s giant galaxies and very bluish in color, indicating they are ablaze with star birth.”

    Makes sense if those (blue/white) objects were close by in our “non accelerating universe”.

    “The images appear red because of the galaxies’ tremendous distance from Earth.”

    Does the statement mean the “objects in the images” appear red because some appear blue and some appear white. Could it be that some (red) are at or beyond the acceleration horizon and some (blue/white) are not?

    ” The blue light from their young stars took nearly 13 billion years to arrive at Earth. During the journey, the blue light was shifted to red light due to the expansion of space. ”

    Aghh!! What is the HUDF and GOODS cameras showing us or was this image rendered to show what was happening back then.
    Still confused and before you guys give me a hard time, I truly have searched for this answer and if it was given to me, it certainly went completely over my head and yes I’m a bit embarrassed.

  25. Will! don’t be embarrassed! as nobel prize winning physicist John Wheeler once put it – “If you are not completely confused by quantum mechanics, you do not understand it.”

    little clue to start you thinking? ride the wave, baby… space is curved.

    in a small region of spacetime, we can think of it as we always have – static – flat – no geometry. but what happens over a great distance? what happens to space and time when it encounters a black hole? what happens to the fabric of space each time it enounters gravity?

    Wheeler also said: “”The frequency of light is also affected by the gravitational field of the universe, and it is neither useful nor strictly correct to interpret the frequency shifts of light…in terms of the special relativistic Doppler effect.”.

    In other words, when you are looking at these photographs, you aren’t seeing the Doppler effect in visible light, the colors you are seeing are the combined (over overpowering) light of the stellar age of the galaxy. Young star-forming galaxies are gas rich and high in ultraviolet spectral energy distribution – that’s why they appear blue. Older galaxies, where new star formation has nearly ceased. They appear red because they stopped forming stars long ago and the longest-lived stars radiate most of their light at red or infrared wavelengths..

    the cameras are showing us what happened back then – because this wavelength of light has only reached us now…

    and after it’s been around a curve or two.

    gentlemen? you may shred me now. 😉

  26. Will says:

    Ok Tammy,
    So what I asked in my original Q. Is it the elemental chemistry that is showing color in the different objects? Based on your explanation, the answer seems to be yes. Now back to red shift due to acceleration. Do I understand that even though an object visually shows up blue or white that a spectral shift toward “red is detected instrumentally? And, that old cool red stars are “redder” due to the Doppler shift/acceleration.
    Now another naive Q. How can an entire galaxy be “old” and red and right next door, another galaxy is new and “hot” and blue?
    I know you busy…. I’ll continue to research some more.

  27. Will says:

    I forgot to say that I appreciate your taking time out for me.
    Thank you once again . Will

  28. Anaconda says:

    Stereo is nice if you can get it, but more important is what causes the fundamental dynamics of the Cat’s eye?

    Notwithstanding the conventional assumptions, it has been observed that the X-rays emitted are from sychrotron radiation, electrons spiralling around a magnetic field, an electric current, therefore, electromagnetism is at the very least a component of the dynamics involved in the Cat’s eye.

    It would, therefore, seem advisable to explore and determine the extent of electromagnetism’s role as a causative factor in the formation and development of the Cat’s eye nebula.

  29. Frances says:

    I really can’t get the stereo bit and I so want to! It’s so beautiful even in mono. Should I move my eyes further or nearer to the screen? I’ve tried half an inch away, and across the room and all the way in-between, but a hint of where to start would help.

    I can’t keep my eyes crossed for long enough.

  30. i’m with ya’, will…. yes, both read and blue shift is detected instrumentally – but the words are misleading. if a galaxy (for example) is moving towards us, it’s shifted towards the blue side of the electromagnetic spectrum – away, to the red. while photographs are done in a portion of the electromagnetic spectrum we’re only seeing

    R —————— > — < -------------------- B this much in a photograph. doppler shift is taking into consideration from one end to the other. so, it could be a young, blue galaxy in that little --- photgraphic band, but shifted all the way over toward the R as far as its "whole spectrum" doppler position is concerned. just as it could be an old, red, dead galaxy that we see in the --- visual band could be blue-shifted when all of its "whole spectrum" light is taken into consideration pushes it toward the coming at us - or B - end of the scale. hmmmm.... let's try something! RbbRbbbbRbbbbbbbRbbbb >RRR< bbbbRbbbbRbbbbRbbbbRbbbRbbbB if you were to look at this, kinda' like our photoscale, right in the center where it what photographed, you'd see red. but add up all the spectra, and who wins? the B. therefore it would be a red galaxy in the visual portion... but blue-shifted. make sense? old, dead, red galaxies just aren't producing new stars anymore - or at least not 'en mass'. they're comprised mainly of stellar II populations and simply aren't sharing "fuel" the way population I stars do. maybe these galaxies are exhausted because they've been stripped by interactions with their neighbors... maybe that's what happens when they get old... maybe we're seeing them through a giant intergalactic dust cloud... but the most predominant theories say their materials were robbed by the starforming galaxies next door! for those who have trouble seeing stereo? try making the image a different size. the cross version seems to work the best and you almost have to be level with the screen. keep trying!

  31. Will says:

    Thanks once again Tammy,

    Still confused (too many variables but, I won’t take any more of your time. I’ll keep searching.

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