The unlit side of the rings Options

[ugordan]

The rings about a quarter of the way up form the bottom of this image look distorted.

I assume you mean geometric distortion, the rings in the upper half being curved less? That's perfectly normal when viewing a ring ansa. It's just an optical illusion.

[ugordan]

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.

[ugordan]

Finally, did someone noticed this very odd image?
http://saturn.jpl.nasa.gov/multimedia/imag...eiImageID=80270
Image explainations refers to "SATURN-ERING" but I suspect that this bright strip is another piece of main rings, partially eclipsed by saturn shape + shadow... other ideas?

Enceladus or Mimas (at around 90 deg phase) entering eclipse while the camera is staying pointed at the rings?

EDIT: Geez... apologies for the triple post, I assumed the board sw would automatically merge them when posted on a short timescale.

[pat]

[quote name='ugordan' date='Aug 1 2006, 11:21 AM' post='63268']
Enceladus or Mimas (at around 90 deg phase) entering eclipse while the camera is staying pointed at the rings?

The streaked satellite is actually Janus. Thats a very long exposure image (100-200 seconds) tracking some point in the ring plane. The raws site is listing the target as E ring probably because thats the target model used for the exposure calculations. The camera command (ioi) files have two entries for target, 'TARGET_DESC' and 'TARGET_NAME' . TARGET_DESC is supposed to describe the object the image exposure was calculated for while TARGET_NAME indicates the object/position that the camera is actually tracking. Often these are the same, but not always. Its the TARGET_DESC keyword that makes it into the description on the JPL raw site.

[alan]

Perhaps you're referring to the disuniformities visible as small hue variation is this RGB version (with enhanced saturation):
[attachment=6850:attachment] (start images N00064483/84/86)
Anyway, is something barely visible to me...

[color=#FF0000]EDIT: just posted a short movie showing spokes transit in this region during previous day, the rough texture noted by alan seems to co-rotate with spokes...

Yes, that's what I was referring to

[dilo]

Between the various images coming down now from unlit side, this partially shaded C-ring view is particularly intriguing, with many stars in the background...
What seems odd to me is the long streak on the right of the center (inside the Saturn shadow)... Very similar to an artificial satellite pass in front a stella field, but we are on Saturn so the most probable explaination must be a cosmic ray. A rare one, because a so long track imply strictly radent trajectory and "slow" energy release on the sensor... (we see other CR tracks in this image, but they are shorter as usual).
Note also the Saturn night side barely visible in the very bottom edge...

[Rob Pinnegar]

Between the various images coming down now from unlit side, this partially shaded C-ring view is particularly intriguing, with many stars in the background...

Actually, unless I'm very wrong, that's the inner part of the D Ring, not the C Ring. It is a very nice image.

[alan]

Get your images stitchers ready

Saturn's Rings To Shine As Never Before
September 15, 2006
(Source: Jet Propulsion Laboratory)

Ring scientists have been waiting for this. Finally, after more than two years orbiting Saturn, the Cassini spacecraft reaches one of the ultimate vantage points. The rings should shine with majesty worthy of the "Jewel of the Solar System."
The event is a solar occultation -- when the sun passes directly behind the planet as Cassini looks on. And this is not just any solar occultation; it's a very long one. The Cassini spacecraft will be right where scientists studying the rings want it: far enough from Saturn to be able to image it all and, more importantly, with the Sun blocked by the planet for 12 hours, long enough to properly map the elusive microscopic particles moving within the extended ring system.
Data collected during this observation might also uncover clues about Enceladus' past behavior and aid mission planners in refining ring hazard models for future ring crossings. Thanks to the slow occultation, images taken during this carefully designed orbit may also uncover new ring structures and, at the very least, capture truly spectacular views of the D, F, G and E rings.
"We are all sort of on pins and needles waiting for the results," says Brad Wallis, Cassini Rings Discipline Scientist. "When you get these kinds of high phase angles, very small particles almost focus the light right at the observer. So these faint rings that are so hard to see are going to be considerably brighter and show us details that are just not possible to see in other viewing conditions. All the space between Enceladus and the G ring is probably going to be pretty well lit up. It's really a unique event.'

http://saturn.jpl.nasa.gov/news/features/feature20060915.cfm

[dilo]

Get your images stitchers ready
http://saturn.jpl.nasa.gov/news/features/feature20060915.cfm

Amazing!
Hope they will take also a snapshot of Earth trough A-ring...

[ugordan]

Nice view:

[mchan]

That deserves a wow! Can't figure out the lighting geometry...

[ugordan]

The viewing geometry is similar to the solar occultation sequence last orbit. Cassini's above the ring plane, the sun is below and located at about upper left position. Everything you see is Saturn's nightside and the unlit rings. Saturn's north is to the top. It's striking that while Saturn's southern hemisphere is lit by light reflected off the rings, even the northern latitudes are lit near the terminator by the light forward scattering through the rings. This illumination is noticeably more bluish, probably the effect of the ring particles preferentially forward scattering shorter wavelengths.

[Floyd]

Could someone help explain what I'm seeing in these recent images of the F ring. In these three images a wake gets more and more pronounced, and I would think would point to a moon (as in the picture of Daphnis)

Here are the 3 pictures of interest:
picture 1
picture 2
picture 3

I think I would see Prometheus or Pandora if they were in the picture?

Thanks, Floyd

[remcook]

" (G) NAC image taken on 29 October 2004 showing the multiple strands of the F ring, a streamer of material connecting Prometheus with the F ring, and sheared gaps in the inner strands due to previous apoapse encounters with Prometheus."

from: Cassini Imaging Science: Initial Results on Saturn's Rings and Small Satellites, porco et al. science 2005.

http://www.sciencemag.org/cgi/content/abstract/307/5713/1226

[mchan]

...Saturn's southern hemisphere is lit by light reflected off the rings...

D'oh! I was thinking how there could be a terminator across Saturn when the planet shadow cuts across the rings like that...