Daphnis, July 2010 |
Daphnis, July 2010 |
Jul 5 2010, 10:46 AM
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#1
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Member Group: Members Posts: 655 Joined: 22-January 06 Member No.: 655 |
Moved the Daphnis discussion to a new thread - Admin
I'm really looking forward to the Daphnis images (they should be safely on board Cassini by now) Although planned images are pretty distant for a body of this size, the perturbations of the ring material either side of the Keeler gap behind and ahead of the moon in it's orbit should be spectacular.... |
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Jul 6 2010, 04:23 PM
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#2
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Member Group: Members Posts: 568 Joined: 20-April 05 From: Silesia Member No.: 299 |
I'm really looking forward to the Daphnis images (they should be safely on board Cassini by now) Although planned images are pretty distant for a body of this size, the perturbations of the ring material either side of the Keeler gap behind and ahead of the moon in it's orbit should be spectacular.... You are right, it is spectacular: http://saturn.jpl.nasa.gov/multimedia/imag...1/N00156644.jpg -------------------- Free software for planetary science (including Cassini Image Viewer).
http://members.tripod.com/petermasek/marinerall.html |
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Jul 6 2010, 05:14 PM
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#3
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Senior Member Group: Members Posts: 3648 Joined: 1-October 05 From: Croatia Member No.: 523 |
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Jul 6 2010, 06:41 PM
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#4
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Administrator Group: Admin Posts: 5172 Joined: 4-August 05 From: Pasadena, CA, USA, Earth Member No.: 454 |
I'd hazard a guess that the "almost-miss" was intentional, in order to see the structure in the wakes as well. I'd think it'd be better to capture as much of one of the two wave trains as possible, to see how they change as they get sheared out & damped with time. Nice version, as always! I'll be posting it as soon as the Society website comes back online...
-------------------- My website - My Patreon - @elakdawalla on Twitter - Please support unmannedspaceflight.com by donating here.
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Jul 6 2010, 07:39 PM
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#5
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Member Group: Members Posts: 655 Joined: 22-January 06 Member No.: 655 |
Magnificent!
Worth bearing in mind that the image above encompasses a mere ~ 1/100th of the radial width of the main ring system - it's a real close-up, and yet, I count at least 50 discrete divisions within that 600km or so. Incredible fine-structure, due presumably to various resonances with the nearer moons and moonlets. Perhaps some of these discrete ring demarcations are caused by Mimas, Pandora, Prometheus, Atlas and even Pan. Very noticeable too, that although Saturn is only just 'this side' of equinox, the long shadows demarcating vertical relief have all but disappeared. Simply breathtaking. |
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Jul 6 2010, 07:48 PM
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#6
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Member Group: Members Posts: 796 Joined: 27-February 08 From: Heart of Europe Member No.: 4057 |
Three superresolution Daphnis images. Only part around Daphnis from whole 1024×1024 images.
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Jul 6 2010, 08:46 PM
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#7
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Junior Member Group: Members Posts: 76 Joined: 19-October 05 Member No.: 532 |
I'd hazard a guess that the "almost-miss" was intentional, in order to see the structure in the wakes as well. I'd think it'd be better to capture as much of one of the two wave trains as possible, to see how they change as they get sheared out & damped with time. Nice version, as always! I'll be posting it as soon as the Society website comes back online... Ahh, nope --we'd intended Daphnis to be at the centre of the image. Its yet another example of how uncertainties in the ephemerides of "rocks" and deviations from the predicted spacecraft trajectory can combine to shift moons towards the edge or even completely off frame, especially during close flybys. As it turns out I think that getting greater longitudinal coverage of the edge waves on one side of the gap might actually be better than more limited coverage on both up- and downstream edges. All nine images are 12-bit and in none of them is Daphnis over-exposed, unfortunately the auto-stretch applied to the raws isn't ideal for every image resulting in Daphnis appearing to be over exposed. |
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Jul 6 2010, 08:46 PM
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#8
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Member Group: Members Posts: 796 Joined: 27-February 08 From: Heart of Europe Member No.: 4057 |
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Jul 6 2010, 08:51 PM
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#9
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Senior Member Group: Members Posts: 3648 Joined: 1-October 05 From: Croatia Member No.: 523 |
All nine images are 12-bit and in none of them is Daphnis over-exposed Most excellent! -------------------- |
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Jul 6 2010, 09:10 PM
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#10
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Member Group: Members Posts: 655 Joined: 22-January 06 Member No.: 655 |
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Jul 6 2010, 10:07 PM
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#11
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Member Group: Members Posts: 909 Joined: 4-September 06 From: Boston Member No.: 1102 |
Lots of ground (ring?) truth for the modelers. Really fantastic images. I love the images of Daphnis, but the ring dynamics is totally awesome.
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Jul 6 2010, 10:52 PM
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#12
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Member Group: Members Posts: 107 Joined: 29-January 09 Member No.: 4589 |
In, for example, http://saturn.jpl.nasa.gov/multimedia/imag...1/N00156646.jpg we can see a lot of granularity in the outermost ring edge. This may be a naive question, but are we looking at individual ring particles here?
-------------------- Protein structures and Mars fun - http://www.flickr.com/photos/nick960/
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Jul 6 2010, 11:24 PM
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#13
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Member Group: Members Posts: 909 Joined: 4-September 06 From: Boston Member No.: 1102 |
According to Emily's blog, the gap is 42 km across, so the structure you see at the outer edge are clumps on a scale of about 1 km. Particle themselve are mostly meters to mm, 10-3 to 10-5 smaller.
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Jul 7 2010, 02:42 AM
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#14
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Solar System Cartographer Group: Members Posts: 10131 Joined: 5-April 05 From: Canada Member No.: 227 |
"Very noticeable too, that although Saturn is only just 'this side' of equinox, the long shadows demarcating vertical relief have all but disappeared. "
Actually when you look carefully you can see lots of small shadows in these images. The real problem is just that the light direction is not ideal for seeing shadows at their best. OK, not 'long shadows', I grant you, but there's quite a lot going on all the same. Phil -------------------- ... because the Solar System ain't gonna map itself.
Also to be found posting similar content on https://mastodon.social/@PhilStooke NOTE: everything created by me which I post on UMSF is considered to be in the public domain (NOT CC, public domain) |
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Jul 7 2010, 02:52 AM
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#15
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Merciless Robot Group: Admin Posts: 8783 Joined: 8-December 05 From: Los Angeles Member No.: 602 |
It's a real stunner, all right... well done yet again, Cassini people!
Yeah, it looks like there are some shadows from things <1 km in there to me, too. Clumps of particles? -------------------- A few will take this knowledge and use this power of a dream realized as a force for change, an impetus for further discovery to make less ancient dreams real.
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