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Faint Ring Thread, Saturn's D, E and G rings
Rob Pinnegar
post Jul 17 2005, 08:23 PM
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There are two new "Raw Images" up that give a good view of Saturn's D Ring. As of today (July 17th) they are on the first page of the Raw Images section. The better of the two is image number W00009347.

The very narrow inner ringlet is called D68 and it is the innermost well defined ringlet of the entire ring system -- it's only about 7250 kilometres above the cloud tops, about half-way from the planet to the inner edge of the C Ring. If you search the "Saturn-D Ring" section of Raw Images, there is a nice narrow angle view (N00035241) which I am pretty sure is a close-up of D68. D68 is an oddball, it really is sort of "in the middle of nowhere".

The brighter ringlet in the upper right is called D73. About a thousand kilometres inward from D73, there is a noticeable "dark zone". In the Voyager images, there was a third bright narrow ringlet inside this zone, D72, which seems to be gone now, strangely enough. The relevant Voyager images are Voyager 1 image 34946.50, and Voyager 2 image 44007.53. If the diffuse ringlet at the inner edge of the "dark zone" is what is left of D72, it looks to have migrated a bit closer to Saturn in addition to spreading out a lot. (By the way, I'm not making up these ringlet designations on the fly -- they are given in a paper by Mark Showalter that was published in Icarus in 1996, which is pretty much the only major paper on the D Ring.)

To give some idea of scale, the three bands of material in the far upper right corner are part of the innermost ringlet of the C Ring (this can also be seen on some images of the rings taken on May 3rd of this year).

Since it is so faint and doesn't appear in many images, the D Ring rarely attracts much attention. But it's kind of neat to look at if you haven't seen it before, particularly because of D68, which is sort of the "anti-F ring" in a way.
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ugordan
post Apr 8 2007, 03:12 PM
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What do you make of this image: http://saturn.jpl.nasa.gov/multimedia/imag...iImageID=106655?

It's apparently a long exposure, motion-compensated image targetting a section in the main rings, but I'm puzzled by that sharp gap in the star trail. The way I see it is there had to be an unusually discrete and opaque segment of the rings there, so opaque that there's virtually no starlight passing through. There's also a segment to the left where the starlight is faded a bit but there doesn't appear to be anything out of the ordinary there.

Weird.


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- Rob Pinnegar   Faint Ring Thread   Jul 17 2005, 08:23 PM
- - volcanopele   Thanks for the treatise on the D-ring. Are there ...   Jul 17 2005, 08:30 PM
|- - Rob Pinnegar   There is some discussion of confinement mechanisms...   Jul 17 2005, 09:15 PM
- - Ian R   Hi Rob, What's the best way to get a copy of ...   Jul 18 2005, 08:00 AM
|- - Rob Pinnegar   Hi Ian, That's a really nice shot of the G R...   Jul 18 2005, 02:17 PM
- - edstrick   After the historically known A, B and C rings, rin...   Jul 19 2005, 09:46 AM
|- - dvandorn   Besides, while each of these classic ring segments...   Jul 19 2005, 10:19 AM
|- - Rob Pinnegar   [quote=dvandorn,Jul 19 2005, 04:19 AM] After havi...   Jul 19 2005, 07:37 PM
- - Ian R   I have collected together the best images of the D...   Jul 21 2005, 07:33 PM
|- - Rob Pinnegar   Hi Ian, Your identification of D68 and D73 in th...   Jul 22 2005, 01:10 AM
|- - Rob Pinnegar   Can't resist resurrecting this thread to point...   Aug 19 2005, 09:00 PM
|- - Rob Pinnegar   The following excerpt, from the last post I put up...   Sep 6 2005, 04:45 PM
- - Rob Pinnegar   I've learned something interesting in the past...   Sep 16 2005, 02:44 AM
- - Rob Pinnegar   Just for the sake of completeness, I thought I...   Oct 4 2005, 10:15 PM
- - Ian R   Great work Rob! Due to the general lack of inf...   Oct 7 2005, 02:40 PM
|- - dilo   QUOTE (Ian R @ Oct 7 2005, 02:40 PM)Great wor...   Oct 7 2005, 09:06 PM
- - alan   Nice views of the G-ring. Anyone know why it has s...   Oct 26 2005, 01:00 AM
|- - pat   QUOTE (alan @ Oct 26 2005, 02:00 AM)Nice view...   Oct 26 2005, 06:27 PM
|- - Rob Pinnegar   QUOTE (pat @ Oct 26 2005, 12:27 PM)dare I say...   Oct 26 2005, 07:47 PM
- - BruceMoomaw   Since the G Ring is located between Mimas and the ...   Oct 27 2005, 07:11 AM
|- - Rob Pinnegar   QUOTE (BruceMoomaw @ Oct 27 2005, 01:11 AM)Si...   Oct 27 2005, 03:18 PM
- - SigurRosFan   PIA07643: G Ring Aglow http://photojournal.jpl.na...   Dec 1 2005, 04:00 PM
|- - Rob Pinnegar   Hmmm. Can anyone else besides me see two "bou...   Dec 2 2005, 06:01 AM
- - alan   Is the glow above and below the rings real or an a...   Dec 16 2005, 05:11 AM
|- - Rob Pinnegar   QUOTE (alan @ Dec 15 2005, 11:11 PM)Is the gl...   Dec 16 2005, 05:43 AM
- - Rob Pinnegar   By the way, since I'm here... just as a follow...   Dec 16 2005, 03:46 PM
|- - dilo   Elaboration of G ring image W00012790   Jan 5 2006, 07:28 AM
- - Rob Pinnegar   There are quite a few new images of the D Ring now...   Jan 20 2006, 11:34 PM
- - alan   The Enceladus Ring QUOTE An interesting feature o...   Apr 27 2006, 02:04 AM
|- - Rob Pinnegar   Interesting. IIRC, a similar phenomenon occurs i...   Apr 27 2006, 03:11 PM
- - BruceMoomaw   It may be simply that Enceladus' south-polar p...   Apr 27 2006, 07:20 PM
- - Rob Pinnegar   In the past week or so some new G Ring images have...   Jun 7 2006, 05:04 PM
- - jsheff   And, lest we forget, there's the ring that Cas...   Jun 9 2006, 05:02 PM
- - Rob Pinnegar   Well, here we go again. There are some nice new ...   Aug 1 2006, 10:48 PM
- - Ian R   Thanks to Rob's earlier research, I've pic...   Aug 2 2006, 02:57 AM
- - Rob Pinnegar   A lot of new ring images have gone up in the past ...   Sep 15 2006, 07:08 AM
- - Ian R   Here are two great recent Cassini pictures of the ...   Sep 21 2006, 10:50 AM
- - remcook   someone can't draw straight lines... (sorry, b...   Sep 27 2006, 08:09 PM
|- - ugordan   QUOTE (remcook @ Sep 27 2006, 09:09 PM) s...   Sep 27 2006, 08:39 PM
- - Rob Pinnegar   In the news today... some new theories about a pos...   Oct 12 2006, 04:33 AM
- - Rob Pinnegar   A neat abstract regarding the G Ring and resonance...   Nov 12 2006, 06:29 PM
- - Rob Pinnegar   Yet another batch of D Ring shots are online today...   Mar 7 2007, 02:28 AM
- - elakdawalla   It probably has to do with the high-inclination or...   Mar 7 2007, 03:58 PM
- - ugordan   What do you make of this image: http://saturn.jpl....   Apr 8 2007, 03:12 PM
- - nprev   Either that, or a one-in-a-million chance occultat...   Apr 8 2007, 03:23 PM
- - alan   This looks like a good opportunity to observe the ...   May 10 2007, 02:45 PM
- - bdunford   What are we seeing in this image that was targetin...   Jun 1 2007, 07:45 PM
- - Rob Pinnegar   Just as a news note: There's a recent D-Ring...   Jul 26 2007, 06:52 PM
|- - ugordan   Two long exposure images of the G ring: http://sa...   Aug 18 2008, 12:10 PM
- - Floyd   I agree that it looks like something very interest...   Aug 18 2008, 06:17 PM
- - bdunford   If confirmed, I vote they name the moonlet after y...   Aug 18 2008, 06:51 PM
|- - ugordan   LOL!   Aug 18 2008, 06:59 PM
- - ilbasso   Any chance that it's the Millennium Falcon try...   Aug 19 2008, 11:46 AM
- - jasedm   Well spotted Gordan! The fact that it appears...   Aug 19 2008, 12:47 PM
- - Ken90000   Personally, I think it is awfully bright to be an ...   Aug 19 2008, 06:05 PM
|- - tedstryk   During the ring plane crossing in the 1990s, Hubbl...   Aug 23 2008, 03:13 PM
- - Floyd   Nice series of 10 G-Ring crossing images from Augu...   Aug 23 2008, 04:26 PM
- - Floyd   Also two more pictures of the clump taken on Augus...   Aug 24 2008, 01:23 AM
- - Floyd   The team now has good orbital data on the G-Ring o...   Aug 24 2008, 01:05 PM
|- - Rob Pinnegar   This is very interesting. The two ends of the sm...   Aug 24 2008, 01:42 PM
|- - ugordan   QUOTE (Rob Pinnegar @ Aug 24 2008, 03:42 ...   Aug 24 2008, 01:50 PM
- - jasedm   The follow-up observations lend weight to the idea...   Aug 24 2008, 02:22 PM
|- - ugordan   We're talking about the G ring.   Aug 24 2008, 02:25 PM
- - jasedm   Oops, getting my rings mixed up   Aug 24 2008, 02:32 PM
|- - Juramike   QUOTE (jasedm @ Aug 24 2008, 10:32 AM) Oo...   Aug 24 2008, 02:48 PM
- - Floyd   No G-Ring images on the August 29th (unless I miss...   Sep 4 2008, 12:16 PM
- - Ken90000   Aren't we still in Solar Conjunction?   Sep 4 2008, 02:04 PM
- - Floyd   Yes we are in conjunction, but comming out. There ...   Sep 6 2008, 03:00 PM
- - Floyd   Nice image of Anthe arc from the news writeup. ...   Sep 6 2008, 03:16 PM
- - Floyd   According to Ciclops Looking Ahead for Rev 84, on ...   Sep 10 2008, 11:28 PM
- - Floyd   I can't see any clumps of interest in the G-Ri...   Sep 15 2008, 07:33 PM
- - Floyd   Some nice images of Ering which sure look a lot li...   Oct 29 2008, 02:01 AM
- - volcanopele   No, that's definitely the G ring. Not sure wh...   Oct 29 2008, 03:44 AM
- - ngunn   Nice bump with shadow: http://saturn.jpl.nasa.gov/...   Dec 10 2008, 09:46 AM
- - Phil Stooke   A bit late - but that E-ring image is presumably l...   Dec 10 2008, 03:11 PM
|- - ugordan   Again, a shot of the clump/moonlet in the G ring, ...   Feb 2 2009, 02:28 PM
- - volcanopele   Tiny Moonlet Within G Ring Arc http://ciclops.org/...   Mar 3 2009, 08:55 PM
- - stevesliva   ...and I just read about it on Emily's blog. ...   Mar 3 2009, 10:53 PM
- - volcanopele   The one in January 2010 is in the 10000-20000 km r...   Mar 3 2009, 11:52 PM
- - elakdawalla   Huh, I didn't realize you could get that close...   Mar 3 2009, 11:57 PM
- - volcanopele   We are nicely out of the ring plane at the time, s...   Mar 4 2009, 12:05 AM
- - nprev   Just restating congrats to Gordan for spotting thi...   Mar 4 2009, 12:14 AM
|- - ustrax   QUOTE (nprev @ Mar 4 2009, 12:14 AM) Just...   Mar 4 2009, 11:55 AM
|- - ugordan   QUOTE (ustrax @ Mar 4 2009, 12:55 PM) May...   Mar 4 2009, 12:01 PM
- - canis_minor   FYI next Wednesday is a close encounter to Aegaeon...   Jan 23 2010, 05:59 AM
|- - dilo   On April 18 Cassini made an interesting sequence o...   Apr 27 2010, 10:42 AM
- - stevesliva   Oddly, I think, the Cassini status noted this: QU...   Aug 5 2010, 10:04 PM
- - Hungry4info   Agaeon is a satellite, the G-arc is a ringlet.   Aug 5 2010, 10:09 PM


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