CometWatch – the movie

As the incredible year of 2014 draws to a close, we have prepared a small treat for all of the readers of this blog who have followed Rosetta's progress over the months, in particular those who like to download images and play with them.

We started our CometWatch in July, when Rosetta was still a few thousand kilometres away from Comet 67P/Churyumov-Gerasimenko. We saw this curiously-shaped comet grow larger and richer in details as the spacecraft got closer and closer until rendezvous at 100 km on 6 August. The NAVCAM images released over that period provided a good overview of our approach to this amazing new world.

In September, as we drew closer to the comet, we had to switch to taking four-image mosaics in order to ensure that we could cover enough of it for navigation purposes. Since then, we have been publishing some of these four-image sets as montages and mosaics, as well as releasing the individual frames so that you could work with them and create your own mosaics. Some have been taken within 8 km of the surface of 67P/C-G, providing amazing views.

But to mark the end of this exciting year, instead of just one new image, montage, or mosaic, the last CometWatch release of the year is ... a movie, featuring no less than 24 montages based on NAVCAM images taken between 19 November and 3 December 2014. A reduced version of the movie can be seen inline here, but the full-sized version is available if you click through.


Animation comprising 24 montages based on Rosetta's NAVCAM images acquired between 19 November and 3 December 2014. Credits: ESA/Rosetta/NAVCAM – CC BY-SA IGO 3.0

These images were taken while Rosetta was in a 30-km orbit around the comet (see the second half of this video showing the trajectory of the spacecraft after 12 November). As usual, each montage comprises four individual images taken over a 20-minute period, at either around 11:00 UT (12:00 CET) or 23:00 UT (0:00 Next Day CET). At 30 km from the comet's centre, the pixel scale is about 2.56 m/pixel.


The path of Rosetta after 12 November 2014. Credit: ESA

As Comet 67P/C-G rotates with a period of 12.4 hours, images taken at 12-hour intervals result in views that are slightly offset with respect to one another, as the comet will have completed slightly less than a full rotation in that time.

In addition, there is also the orbital motion of Rosetta with respect to the comet: over the two weeks over which the images were taken, Rosetta completed almost one full orbit at 30 km from the comet.

Taking these factors into account, we have ordered the images according to the apparent rotation phase in order to make a movie. In fact, we have sorted the images in an almost reverse chronological sequence, starting with a montage taken on 2 December, then working backwards one day at a time to 19 November. The last montage in the sequence, however, is from 3 December.

Given the limited time available to us in the run up to Christmas, this is all we have been able to do: a phase-ordered sequence of montages made into a movie. There has been no processing of the images apart from the removal of the basic instrumental signature.

But we know that you can do better, and as a thank you to everyone who has produced and shared dozens and dozens of excellent NAVCAM mosaics and images over the past few months, we’ve made the full set of 24 montages and of 96 individual 1024 x 1024 pixel frames available for download.

So, if you have the time over the holiday period, we invite you to create your own mosaics and perhaps even your own movies, and to share them on your social networks under the terms of the Creative Commons licence that applies to NAVCAM images (CC BY-SA IGO 3.0). Let us know about them in the New Year.

For those who want to know exactly where the spacecraft was at the moment when each image was taken and perhaps factor that into their movie-making, the so-called 'SPICE' files for Rosetta are available here, and the tools to read and process those files can be found here. Few parameters are already included in the filenames of the provided images, such as rotation phase, date and time (rot.phase_ESA_ROSETTA_NAVCAM_yymmddThh).

We hope you have enjoyed following our CometWatch in 2014 and we are looking forward to another exciting year as 67P/C-G gets closer and closer to the Sun. Rosetta will be there to monitor its changes and discover what it really means “to live with a comet”.



  • Mattias Malmer says:

    Challenge accepted!

  • Bill Harris says:

    Sounds like a fun invitation! I've been toying with that idea, and your GIF animation is proof-of-concept.

    Have a Great Holiday!


  • Hans says:

    Beautiful results again! I can't wait to here more in 2015. Just curious, why didn't you make this movie (animated gif) from the joined images, i.e. without the black frame in the middle, like you did with some of the highres images that you posted on the blog? Also, your link to "this video from the trajectory" in the 5th paragraph, does not link to a video but to a JPG image.

    • Claudia says:

      Hi Hans,

      Thanks for spotting this, the link has been fixed now and redirects to the video of Rosetta's trajectory.
      As explained in the post, given the limited time available these days, there was no processing of the images apart from the removal of the basic instrumental signature.

      Best wishes

      • Mark McCaughrean says:

        And another slightly more subtle point that anyone accepting "the challenge" is going to have to deal with, is that making mosaics from the 4-image montages involves quite a few compromises, due to the rotation of the comet and the movement of Rosetta during the sequence.

        This can involve using distortion parameters in mosaicing programmes and some slight fudges in terms of small surface features which have changed during the sequence.

        That's ok for a single mosaic, but these compromises could be somewhat more cruelly exposed when it comes to making a smooth movie out of a series of them.

        But I think you're up to the challenge ... 😉

  • Found a nice little "Philae glint"...

    Prolly nothing but it matches most criteria...

    • Habib Rij says:

      I am always interested to hearing where the Philae lander is right now and following updates from this blog.

      Is your the location you indicated within the predicted resting place?

      • Herobrine says:

        It appears that it is. The same "glint" is also visible in the 7 December CometWatch image.

        I've annotated one of the 22 November NAVCAM images used in Mattias' GIF, the December 7 NAVCAM image I linked above, and the CONCERT landing estimation image with marks of recognizable features to show approximately where that "glint" lies in the estimated landing area.

        22 November:
        7 December:
        CONCERT landing area estimation: (white dot represents the "glint", already visible in the other two images)

        I can't say yet that I'm convinced that the "glint" is Philae; there are multiple other persistent bright spots of similar size visible in these images, though this is the only one I've seen that falls within the estimated landing area. I think later, I'll look for a NAVCAM image that shows that spot in favourable lighting conditions prior to the landing. If I find any, and they show no bright spot there, I'll be nearly convinced that's Philae. Until then, I won't get very excited.

  • Tycho says:

    Thank you very much for this amazing Christmas gift!

  • masanori says:

    Thank you very much Claudia and all who have remained in the offices to give updates to people like me until last minuts before Christmas. Hope you all have a merry Christmas and Happy New Year!!

  • Bill Harris says:

    Preliminary enhancement of ESA/Rosetta/Navcam/BlogTeam animated GIF image ESA_Rosetta_NAVCAM_30km_movie_small.gif
    This is just a prelim version to get the image in before the Holiday Break. Never could get the last frame of the animation to fully load, and I'll need do much more work on the individual frames during the Break.

    This movie is enhanced to show the dust jets more clearly.


    • Robin Sherman says:

      Nicely done Bill. The tweaking of the contrast helps illuminate the cliffs of the neck and some of the "Dark Side" in the Southern "Hemiduck"

    • Dave says:

      Nice one Bill
      have a merry xmas.

      also to all the esa staff, sorry for all the griping, have a great Xmas

    • Wayne says:

      Thank you!

  • Carlo Marchiori says:

    I don't believe you don't know at this time where the Philae lander exactly is. Maybe if you told us you should show us some more Osiris narrow angle camera, but your contracts doesn't allow it. Could it be?

    • Mark McCaughrean says:

      C'mon, Carlo: give us a break, all right? Of all the opinions expressed on this blog, the kind that perplex me more than any other are the "conspiracy theory" ones.

      If we had located Philae, do you really think we'd keep it secret? Why would we? What would be the point? We know many people are keen for us to find it, and once we do, we'll be more than happy to share that with everyone.

      The fact of the matter is that we have a pretty good idea of the region it's probably located in, based on trajectory analysis and CONSERT data. We've been quite open about that, and this was discussed extensively (and publicly) at last week's AGU meeting.

      New OSIRIS NAC images were taken of this region last weekend (as we'd dropped back down to 20km from 67P), but as was reported during the AGU, those images were on-board still, in the queue to be downloaded.

      I don't know if they're down yet, but even then, it's probably going to take some careful work to find plausible candidates and then verify them. This work will be done by the OSIRIS team: we at ESA don't have access to those images, as we've explained many times here before, under the terms of the proprietary period.

      But we're confident that as soon as a credible identification of Philae has been made, the OSIRIS team will share those images with us and they will be jointly released to the web as soon as possible (albeit keeping in mind that we'll be very short-handed over the Christmas and New Year period).

  • Kamal Lodaya says:

    Movies are good to see, but as a base language for 2015 we need a map. Since November Rosetta has been making a map, and from the AGU presentations it is clear that the team has indeed a nomenclature in place. It would be good to have it out so that people can refer to locations on the comet using the same language.

  • duckdiver says:

    I've been lurking on and off tis blog for a while, entranced by the info, links, speculations, the contributors, many thanks to you all.
    With regard to Mark's "Perplexity"; As a long time Skeptic, I've gotten a little bored over the years with science vs faith arguments, despite the negitive personal and social Impacts I believe "Belivers" create for the world, and so was pleasantly surprised to see familier falicies and reasoning appear in a whole new context and subject, real time , rather than perplexed.
    Again, many thanks to all for the hours of labor youv'e put into your posts, they have been much appreciated.
    Also wounder if the granulations particals are similier to those that create the sand dunes in titan?

  • Daniel says:

    While I don't think I will try my hand at an animation, I did mark out the first touchdown position on a number of images. I also indicate where the CONSERT defined final landing site area should be, but only with an arrow that points at it in a very rough "this general area" sense. They aren't the full size versions either, use them as a guide while looking at the full versions here on the ESA site instead.
    So here you go, hope I didn't mess up somewhere:

    ( is the latest posted CONSERT estimation)

    Image credits ESA/Rosetta/NAVCAM - CC BY-SA IGO 3.0
    Images are from:

    First row
    2014.09.21 -
    2014.11.06 -
    2014.12.02 -

    Second row
    2014.11.20 - from the movie images
    2014.08.17 -
    2014.12.09 -

    Third row
    2014.09.14 -
    2014.10.30 -
    2014.12.07 -

    There are a few more images posted that does contain the landing site or first touchdown point, I didn't do them all.

  • Thomas says:

    Challenge accepted! Already 9 mosaics done, 15 mosaics left!

  • Thomas says:

    I accepted the challenge and here is the movie I made:

    I'm also working on a smoother version, using a morphing software to interpolate frames between each mosaic:

    • Nick tiller says:

      The smoothed version is extraordinary like everyone else I look forward until u complete keep up the good work

  • plata says:

    Here's my movie:!ClIJDZTHCmvWWK02pJ9Tk77mV8IIWwUphylyH3ps
    Images have been joined using Hugin.

  • Sergio Muraro says:

    My movie:

  • emily says:

    Thanks for the great movies so far! We hope you enjoyed this challenge!

    • Thomas says:

      A lot of my holiday time was dedicated to do it and it was really funny. What I like during stitching process is that you have to look closely to each NavCam picture to add control points. Meanwhile, you often discover very interesting landscapes, cliffs, holes, boulders...
      I hope we'll have other opportunities to make such movies!
      Meanwhile, I'll finish my smooth version of the NavCam movie.

      • plata says:

        Totally agree. It was interesting to see how different the sides are in fact. One side seems to be more "rocky", while another looks like a slope where an avalanche went down.

  • marco says:

    The smooth version is amazing Thomas!
    Returning to the issue Philae: I think only way to photograph the little guy has to wait for the head of 'duck and in particular the large crater, is facing the Sun with Rosetta aligned between the two (warning: do not shade with Rosetta : - )).
    My guess would explain the flight times between the second and the third touch-down.
    Also the morphology of the soil at the base of a cliff is likely to be comparable to that recovery from Philae around itself.
    Also plenty of shade in all the footage is there.
    The photos used are copyright ESA

  • There's not a lot you can do with 24 frames (that's less than a second of timelapse/animation)

  • Daniel says:

    Thanks for the movie versions. They really make you appreciate how jagged the comet is. Hopefully we will see a few more attempts at it still. Could be interesting to use a 3d model to fill in the gaps.

  • Thomas says:

    I made two more movies of the rotation of the comet. These smoother versions were obtained with a morphing software to interpolate frames between each mosaic. There are still some artefacts and distorsion effects but I'm pretty happy with the result.
    Video 1 :
    Video 2 :

  • Nick tiller says:

    Thanks for posting Thomas a lot of hard work went into those, I like the artefacts the way the comet seems to breathe and flex in a few frames

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