By Phil Plait | March 2, 2007 12:35 pm

This has to be seen to be believed– the STEREO spacecraft captured a series of images of Comet McNaught, and the animation is, well, it’s nothing short of spectacular. Stunning. Jaw-dropping. It’s like Star trek (and more on that later).

STEREO is actually two satellites on solar orbits. They look sunward, taking data and getting a 3D view of our nearest star. One of them happened to be able to see the comet, and the scientists back home produced that amazing animation.


Comments (20)

  1. Jaw drops….


  2. Melusine

    What causes that ring that goes off to the left side before the above snapshot you posted takes place? Just noticed it and wondered what caused it.

    Very pretty!

  3. Jason

    Wow, indeed. Check out the movie of the Moon transit on the STEREO site as well. Most impressive. ūüėČ

    Great blog BTW…

  4. GBlade

    Cool vid, but what are the other two bright objects moving against the background?

  5. Jason– I actually have that blog post about ready to go. The animation wasn’t up yesterday when I looked for it on the STEREO site (I heard about it elsewhere).


  6. bPer

    GBlade: they are Venus and Mercury.

  7. Grand Lunar

    Reality meets space art; incredible!

    Yet another example of how cool unmanned probe science can be. :)

  8. Richard B. Drumm

    Is that the zodiacal light on the right?
    Waaaaay cool! :-)

  9. icemith

    I have spent (maybe) way too much time enjoying the “Eclipse” movie. It is terrific, and given me much to think about.

    With reference to the STEREO link which leads to the ‘movie’, showing the silhouetted moon passing in front of the disc of the sun, I noticed many streaks and spots in many frames. I subsequently checked each frame and was astounded to find so many different *events* with various angles, colors and lengths. There were also many frames with multiple tracks etc. See at 17:40 and 19:20 hours. (I had downloaded the highest quality QuickTime version – about 20Mb’s worth.).

    But I was amazed to see one track right across the moon *and*, maybe the sun too. I realise that these pix would not indicate in which direction the instigator of the streaks was travelling, due to the exposure method – shots taken every ten minutes, and almost certainly very short exposures as we are shooting the actual sun, albeit in the extreme ultraviolet part of the spectrum.

    Now I also realise that as the image was made-up from four seperate images taken (almost) instantaneously. the streaks may be artifacts of that process. But I don’t think so, – well, hoping not so anyway.

    I have catalogued most of the frames with these items, their position, and other brief characteristics. It took a while to slog through the movie, and no doubt have missed some smaller spots and very short streaks. That quite a few would not be moving in a right-angle plane, relative to the Stereo Spacecraft, then their trajectory would be longer than actually shown. Also the fact that each streak is dead straight, seems to indicate they are moving at a relatively high velocity. What could be shown is only the moment of exposure, though I cannot explain instances where spots appear across the moon and further near the sun, all in a line though the exposures are taken ten to thirty minutes apart, at 08:20, 08:30 and at least 08:40 hours.

    But I can’t really identify the streaks or spots as being logically anything substantial. Has anybody any clues as to their identity?


    PS, I am going to post these comments in the NASA Stereo website if I can manage it too.

  10. Hank Cazorp

    This is obviously faked. You can see the stars in the background. ūüėČ

  11. Millimeter Wave

    I just looked at the eclipse video frame-by-frame (I imported it into Vegas Movie Studio, which I happen to have here).

    As far as I can see, the streaks and spots you mention all occur in exactly one frame each, which points towards cosmic rays or some other high energy particles as the likely culprit. This is not unexpected or uncommon in CCD cameras in this type of application.

    By the way, that’s some *monster* CCD blooming going on in the McNaught video ūüėČ

  12. icemith

    > Millimeter Wave… Yeah I tried to think of all the possibilities for the artifacts, but did rule out things like actual “cosmic rays” because I reckoned they would be SO fast as to not leave any trace. Such a variety of traces I thought, would rule it out. But then I am asking the question, so I should not be surprised by the answer, (or answers).

    Sorry that the comment re the STEREO Eclipse appeared in this topic though. I knew I had posted a comment (?)… some would call it half a book… and later could not find it. Eventually the penny dropped and so, as I had copied it to also send to the NASA site, was able to send it to the correct topic. It wasn’t until I had gone to bed that I remembered I had not posted a sorry note (as this is), explaining the unusual double post.


    I had a bit of trouble trying to run the McNaught piece, but I can see what you mean by the, as we used to say, the “blooming blooming”! I shall have to have another look at the topic. (Blooming was a genteel euphanism from another age.)


  13. Millimeter Wave

    the effects of cosmic rays (and other high energy particles) are a well-known and commonly observed phenomenon in CCDs used for astronomical work. The artifacts in the video look exactly like what you would expect from such particles hitting the CCD chip.

    Just to be clear, what is going on is that the CCD is designed to count the number of electron-hole pairs created by photons hitting each pixel sensor over the duration of the exposure. However, if you get some high energy particle passing through camera in a wide diagonal path, it can pass through a large number of such pixels and create a large number of such pairs as it progresses.

    Google for “cosmic ray” and “CCD”. You should find many examples.

  14. What happened to the “more on Star Trek later” bit ?


  15. icemith

    Ah thanks, Millimeter Wave, I can see what you mean now. I will do the google bit. I vaguely remember from long ago now, that that was a problem with early imageing chips, but don’t remember any details, a it was in an area that I had no chance (then), of needing that application. It would have been in Technical mags, I guess in the 80s. I’m surprised that it is not more widely discussed, and that “somebody” has not eliminated the problem.

    Gotta google now.


  16. JB of Brisbane

    Don’t try to snow me; that’s an angel’s wing if ever I saw one!

    Seriously, though, Marcel Duchamp would have been proud of the still image at the top of the post.

  17. J Dubb

    It’s gone now! Where can I see this animation??

  18. Karl

    The original animations and background story are here:


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