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The unlit side of the rings
Bjorn Jonsson
post Jul 27 2006, 10:56 AM
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Cassini has previously imaged the unlit side of the rings but now it is doing extensive observations of the unlit side. For the first time in its mission Cassini is spending a significant amount of time north of the ringplane - earlier it has done so only near periapsis but this orbit is different.

This is a quick RGB composite I did from wide angle images:

Attached Image


I made no attempts to correct the color - this is probably not very far from the true color of the rings. Large color variations are apparent, the C ring and the Cassini division appear much more bluish than the thicker rings (A and B ). It should be noted that these images were very probably downliked with the 12 -> 8 bit encoding which basically means that dark areas appear too bright in this image because I did not correct for this.

It's also interesting to compare this image to Voyager images:

Voyager 1: http://photojournal.jpl.nasa.gov/catalog/PIA02241

Voyager 2: http://photojournal.jpl.nasa.gov/catalog/PIA01955
Voyager 2: http://photojournal.jpl.nasa.gov/catalog/PIA01389
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alan
post Aug 1 2006, 01:57 AM
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The rings about a quarter of the way up form the bottom of this image look distorted.

http://saturn.jpl.nasa.gov/multimedia/imag...2/N00064487.jpg
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dilo
post Aug 1 2006, 05:38 AM
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Alan, I cannot see the distorsion... exactly, which rings and how they are distorted?

PS: thanks for great unlit side view and the beeatiful animation, Bjorn!


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helvick
post Aug 1 2006, 06:04 AM
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QUOTE (dilo @ Aug 1 2006, 06:38 AM) *
Alan, I cannot see the distorsion... exactly, which rings and how they are distorted?

I can see it but to me it looks as if the rings have quite a rough texture - it's almost as if they were drawn by someone with a fairly heavy brush action.
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ugordan
post Aug 1 2006, 10:19 AM
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QUOTE (helvick @ Aug 1 2006, 07:04 AM) *
I can see it but to me it looks as if the rings have quite a rough texture - it's almost as if they were drawn by someone with a fairly heavy brush action.

Three words: image compression, noise & non-flatfielded raw images. You're trying to pull way too much out of them. When calibrated they will likely look very smooth (apart from spokes) at this distance.


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Posts in this topic
- Bjorn Jonsson   The unlit side of the rings   Jul 27 2006, 10:56 AM
- - ugordan   Great composite. I think it's a tad on the too...   Jul 27 2006, 11:30 AM
- - ynyralmaen   Beautiful... one really nice effect that's vis...   Jul 27 2006, 12:28 PM
- - tasp   I recall viewing pictures sent back by Pioneer 11 ...   Jul 27 2006, 01:41 PM
|- - Bjorn Jonsson   Cassini's view of the unlit side of the rings ...   Jul 29 2006, 12:57 AM
- - alan   Speaking of high phase angles, according to Solar ...   Jul 29 2006, 07:45 AM
|- - ugordan   QUOTE (alan @ Jul 29 2006, 08:45 AM) I wo...   Jul 29 2006, 10:30 AM
||- - Bjorn Jonsson   The occultation lasts about 15 hours so there shou...   Jul 29 2006, 07:53 PM
|- - tallbear   I wonder what observations are planned for this. [...   Jul 30 2006, 01:02 AM
- - djellison   Don't they use these sorts of obs for occultat...   Jul 29 2006, 08:40 PM
|- - ugordan   True, both VIMS and UVIS can stare at the sun. Whe...   Jul 29 2006, 09:12 PM
- - alan   The rings about a quarter of the way up form the b...   Aug 1 2006, 01:57 AM
|- - dilo   Alan, I cannot see the distorsion... exactly, whic...   Aug 1 2006, 05:38 AM
||- - helvick   QUOTE (dilo @ Aug 1 2006, 06:38 AM) Alan,...   Aug 1 2006, 06:04 AM
||- - dilo   QUOTE (helvick @ Aug 1 2006, 06:04 AM) I ...   Aug 1 2006, 08:27 AM
|||- - ugordan   QUOTE (dilo @ Aug 1 2006, 09:27 AM) Final...   Aug 1 2006, 10:21 AM
|||- - pat   [quote name='ugordan' date='Aug 1 2006...   Aug 1 2006, 11:42 AM
||- - ugordan   QUOTE (helvick @ Aug 1 2006, 07:04 AM) I ...   Aug 1 2006, 10:19 AM
|- - ugordan   QUOTE (alan @ Aug 1 2006, 02:57 AM) The r...   Aug 1 2006, 10:16 AM
- - alan   QUOTE (dilo @ Aug 1 2006, 03:27 AM) Perha...   Aug 1 2006, 12:53 PM
|- - dilo   Between the various images coming down now from un...   Sep 13 2006, 06:51 AM
|- - Rob Pinnegar   QUOTE (dilo @ Sep 13 2006, 12:51 AM) Betw...   Sep 15 2006, 07:37 AM
- - alan   Get your images stitchers ready QUOTE Saturn...   Sep 15 2006, 10:06 PM
|- - dilo   QUOTE (alan @ Sep 15 2006, 10:06 PM) Get ...   Sep 16 2006, 11:25 AM
|- - ugordan   Nice view:   Oct 2 2006, 09:56 PM
|- - mchan   That deserves a wow! Can't figure out the...   Oct 3 2006, 03:36 AM
|- - ugordan   The viewing geometry is similar to the solar occul...   Oct 3 2006, 06:48 AM
|- - mchan   QUOTE (ugordan @ Oct 2 2006, 11:48 PM) .....   Oct 4 2006, 07:29 AM
- - Floyd   Could someone help explain what I'm seeing in ...   Oct 3 2006, 12:33 PM
- - remcook   " (G) NAC image taken on 29 October 2004 show...   Oct 3 2006, 01:23 PM


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