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

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."

It doesn't say, but the Solar System Simulator shows the occultation - of the planet, not the rings - occurring from about 7:00 UTC to 23:00 UTC on the 15th, which is 3:00 AM EDT -7:00 PM EDT on the 15th. And it does say the images will be sent to Earth on the 17th. They should be spectacular!

I am looking forward to this one too.

Another interesting thing about this set of observations is that, given the long exposure times needed to bring out details in the D, G and E rings, we're probably going to see the inner planets in some of the images. Earth, and especially Venus, will be easiest; each should fill up about a fifth of a pixel (in the wide angle camera).

As luck would have it, the Moon was almost at its greatest elongation from Earth, as seen from Saturn, on September 15th. Seen through the wide-angle camera, it should be about four pixels away from the Earth, and about four magnitudes fainter. I wonder if it will be visible? Guess it will depend on the amount of smearing due to spacecraft motion (which, now that I think of it, would likely cause the Earth to overwrite the Moon anyways).

First images are now posted, including some remarkable, though overexposed, images of sunset behind Saturn...

Shouldn't this thread be moved to the Cassini subforum?

John.

Amazing how bright the "gap" between the outer edge of A ring and the F ring is here. The F ring is brilliant and the Encke gap is notably dusty as well.
It's a shame a vast sequence of Saturn's limb, multi-filter frames got severly overexposed and suffers from charge bleeding. Hopefully the wide-angles will turn out better.

Here's the money shot - Earth (just below the A-ring ansa), Enceladus+plume (upper right), and the E and G rings, as well as the main ring system! North is at the bottom.

John.

Spokes in the E-ring?
http://saturn.jpl.nasa.gov/multimedia/imag...3/W00018033.jpg
http://saturn.jpl.nasa.gov/multimedia/imag...3/W00018036.jpg

Enceladus in the E-ring
http://saturn.jpl.nasa.gov/multimedia/imag...3/W00018011.jpg

E-ring distorted by Enceladus
http://saturn.jpl.nasa.gov/multimedia/imag...3/W00017915.jpg

Diamond ring effect
http://saturn.jpl.nasa.gov/multimedia/imag...3/W00017924.jpg

Ba-Zing!.

Diamond ring.

The stitched/processed HDR version of this image set is going to be utterly spectacular. My thanks to all involved in the mission for the amazing images and the opportunity for nerds like me to see them when they come down.

okay, this one requires an explanation:

http://saturn.jpl.nasa.gov/multimedia/imag...3/W00018018.jpg

The dynamic range involved in trying to capture the 'halo', the lit rings, and the E ring makes it almost impossible to capture in one image - but this is my best guess.

I see that the sequence made the effort to do multiple exposures in each filter set - but there was some down-sampling in some of the exposures. When this lot hits the PDS I'm sure Bjorn et al will work wonders on it Vio+IR is just enough to make something interesting

By explanation - would it be enough to say that just about everything is saturated and scattering of light from the rings is lighting the 'eclipsed' rings as well?

Doug

Reflection of opposition surge off the cloud tops?

Edit : scratch that, the pattern is wrong.

Sunlight reflected of rings onto Saturn, Dark bands are areas where light from cloud tops is blocked by A and B rings. Bright area is cut of in curve at the bottom because this area is north of equator so no sunlight reflected directly from rings

Vision of dream...

Are we in Pitch Black?

Note : we see clearly the shadow of the secondary miror of the objective of the camera on the first pic.

I guess the rings are being lit by light diffracted by the atmosphere (like the red/orange moon seen during a lunar eclispe) and also that reflected from the rings.

Edit: please ignore my above comment.

And a color pic of the "pitch black" scene :

In this one, what's the overexposed elliptical feature inside the limb? Is it an artifact?

It couldn't be a highly-refracted image of the Sun's disc, could it? (I assume not -- isn't that what the continuous ring all the way around the limb is, effectively?)

In neighbouring images (which I guess let more light in) the same region bleeds vertically (1, 2, 3).

Why would they downsample all the images to 512x512 or less?

EDIT: OK I found one that I hoped would be full size:

http://saturn.jpl.nasa.gov/multimedia/imag...eiImageID=83290

http://saturn.jpl.nasa.gov/multimedia/imag...eiImageID=83288

Tethys's shadow is visible in the E-ring
Click to view attachment
Cropped and brightened for this image.
http://saturn.jpl.nasa.gov/multimedia/imag...eiImageID=83289

This image is simply incredible.

Is this a new (albeit very faint) ring between the F and G rings?

Click to view attachment

Could this become known as the H-ring?

http://saturn.jpl.nasa.gov/multimedia/imag...3/W00017882.jpg

Ian.

Wow!!!!!

It occurs to me that if we had gotten images from this vantage point early in the orbital phase of the mission, there would have been no doubt whatsoever that Enceladus is the source of the E ring. You can see the ring material flowing off of Enceladus and smoothing itself into the ring quite clearly.

Amazing, amazing images. As someone said nearly 40 years ago of a somewhat similar view of the Moon, it's worth the price of the trip.

-the other Doug

Nope, that's a wide-angle camera frame. It's a refractor so it doesn't have mirrors. What we're seeing here is possibly the finest image of the calibration lamp and its three supporting rods in front of the optics.

Alan, that Tethys shadow image is awesome, nice catch!
Also, did you notice the complex pattern of the E ring just in the vicinity of Enceladus ("conveniently" caught just at the ring's ansa)? It looks very disturbed.

EDIT: On closer inspection, it's notable the disturbance in the E ring is similar to what Daphnis does. Cassini is above the ring plane (all the images are upside-down) so the orbital motion is counter-clockwise. This implies the ring particles in the inner side have advanced further along their orbit, after being perturbed by Enceladus. The outer edge perturbance is lagging behind the moon. Thus the "wave-like" appearance, though it's not nearly as orderly as with Daphnis, probably because the E ring isn't as confined and is also spread-out vertically. Enceladus is also much more massive than the ring-embedded moons.

Well - they didn't do all of them - but the reason is storage capacity I believe.

Doug

Really a good catch, alan. Herebelow, a processed version of your cropped area within the original context image...

Hi,
wow really impressive pics!!!

Does anybody know a link for a larger version of this overview...

...of the mosaik?

I'm just asking for indentification purposes of all these objects around Saturn - its moons and the visible 'inner planets'.

THX & Bye.

...and this is the rgb composition of the same field (with lower exposure time); there isn't Thetys's shadow but show the amazing Enceladus envelope:
Click to view attachment (original images: W0017910/911/912)

An alternative view of the E/G rings with "extended range" colors (ir3+clear+violet filters), suggesting a compositional difference between inner and outer E ring and respect to G ring:
Click to view attachment (W00018033+enlarged W00018035/036)

Finally, this is a collection of "high dynamic range" images based on the combination of 3 clear filter pictures taken with different exposure time (red channel correspond to the weakest details):
Click to view attachment Click to view attachment

Good eyes. The "H-ring" looks like its at the same distance as Janus and Epimeteus.

That's a nice view! I'm more inclined to say it doesn't mean compositional differences as much as variations in average ice particle size - the smaller the particles, the more shorter wavelengths are scattered and the ring appears bluish. Though, the result here will be less useful as we don't know the different exposures used and thus relative brigthnesses at different wavelengths.

Two pictures to add into this spectacular Cassini gallery.

Sun eclipse by Saturn at different exposures :
Click to view attachment

And the "Pitch Black Like" scenery with three other images :
Click to view attachment

That's a little science fiction rendering.

Absolutely agree. In fact, I was speaking not only of chemical composition but also (and especially) dimensional composition. Such differences were already highlighted inside main rings, now are evident also here due to favorable illumination.
Note that the bluish color of internal E-ring is barely visible also in the rgb image. This suggests that finer particles populates this region (eventually spiraling toward Saturn)... any idea on the dynamic of this segregation?

Ant103, great work!
Is really a little science fiction rendering!
If I'm not wrong, in the second (coulor) image I see some bright, long features inside the Enke division...
Do someone has any idea on their origin?

Okay, I get it now. Those are the rings we are looking at against the illuminated night side of Saturn. Okay, now it makes sense.

I believe the bright spot above the E-ring in the first image and above the G-ring in the second image is the Earth

http://saturn.jpl.nasa.gov/multimedia/imag...3/W00017855.jpg
http://saturn.jpl.nasa.gov/multimedia/imag...3/W00018011.jpg

Nice catch:

http://space.jpl.nasa.gov/cgi-bin/wspace?t...=1&showsc=1

Here is probably the best shot of the new "H-ring":

Click to view attachment

http://saturn.jpl.nasa.gov/multimedia/imag...3/W00017856.jpg

I would agree with Alan that this ring is probably linked to Janus and Epimetheus.

Ian.

The H ring seems much darker and less reflective than the E ring, even (or maybe especially) in this lighting. I'd think this would argue against it being a pure-ice ring. Perhaps it is formed of icy/rocky debris from impacts on Janus and Epimetheus? I guess my first impression is that it's more of a dust ring that an ice ring.

-the other Doug

Handful of new images posted.
This is an odd image of the E-ring. The glow above it reminds me of an aurora. Is it something associated with the spokes or just an odd internal reflection?
http://saturn.jpl.nasa.gov/multimedia/imag...3/W00018094.jpg
http://saturn.jpl.nasa.gov/multimedia/imag...3/W00018092.jpg

It appears to shift between these two
http://saturn.jpl.nasa.gov/multimedia/imag...3/W00018096.jpg
http://saturn.jpl.nasa.gov/multimedia/imag...3/W00018097.jpg

Alan, I suspect is a reflection/diffusion effect from strongly illuminated main rings; this because is visible also in the"best view of H ring" image posted before where it's nature is clear...

Another great catch, Alan! Click to view attachment ...this makes me happy!

dvandorn said "The H ring seems much darker and less reflective than the E ring" - isn't it much more likely that it's just optically thinner?

Phil

Cassini's Solar Eclipse labeled (91 KB):

I can see my house from here (or at least my home planet)! very VERY nice!

The ring you labeled the "F ring" is actually the G ring. Otherwise, great work. Nice to see Mercury included as well.

Thanks! Here's my revised version ...

News Release: 2006-110 September 19, 2006



Scientists Discover New Ring and Other Features at Saturn



Saturn sports a new ring in an image taken by NASA's Cassini spacecraft on Sunday, Sept. 17, during a one-of-a-kind observation.



Other spectacular sights captured by Cassini's cameras include wispy fingers of icy material stretching out tens of thousands of kilometers from the active moon, Enceladus, and a cameo color appearance by planet Earth.



The images were obtained during the longest solar occultation of Cassini's four-year mission. During a solar occultation, the sun passes directly behind Saturn, and Cassini lies in the shadow of Saturn while the rings are brilliantly backlit. Usually, an occultation lasts only about an hour, but this time it was a 12-hour marathon.

Sunday's occultation allowed Cassini to map the presence of microscopic particles that are not normally visible across the ring system. As a result, Cassini saw the entire inner Saturnian system in a new light.

The new ring is a tenuous feature, visible outside the brighter main rings of Saturn and inside the G and E rings, and coincides with the orbits of Saturn's moons Janus and Epimetheus. Scientists expected that meteoroid impacts on Janus and Epimetheus might kick particles off the moons' surfaces and inject them into Saturn orbit, but they were surprised that a well-defined ring structure exists at this location.

Saturn's extensive, diffuse E ring, the outermost ring, had previously been imaged one small section at a time. The 12-hour marathon enabled scientists to see the entire structure in one view. The moon Enceladus is seen sweeping through the E ring, extending wispy, fingerlike projections into the ring. These very likely consist of tiny ice particles being ejected from Enceladus' south polar geysers, and entering the E-ring.

"Both the new ring and the unexpected structures in the E ring should provide us with important insights into how moons can both release small particles and sculpt their local environments," said Matt Hedman, a research associate working with team member Joseph Burns, an expert in diffuse rings, at Cornell University in Ithaca, N.Y.

In the latest observations, scientists once again see the bright ghost-like spokes -- transient, dusty, radial structures -- streaking across the middle of Saturn's main rings.

Capping off the new batch of observations, Cassini cast its powerful eyes in our direction and captured Earth, a pale blue orb, and a faint suggestion of our moon. Not since NASA's Voyager 1 spacecraft saw Earth as a pale blue dot from beyond the orbit of Neptune has Earth been imaged in color from the outer solar system.

"Nothing has greater power to alter our perspective of ourselves and our place in the cosmos than these images of Earth we collect from faraway places like Saturn," said Carolyn Porco, Cassini imaging team leader at the Space Science Institute, Boulder, Colo. Porco was one of the Voyager imaging scientists involved in taking the Voyager `Pale Blue Dot' image. "In the end, the ever-widening view of our own little planet against the immensity of space is perhaps the greatest legacy of all our interplanetary travels."

In the coming weeks, several science teams will analyze data collected by Cassini's other instruments during this rare occultation event. The data will help scientists better understand the relationship between the rings and moons, and will give mission planners a clearer picture of ring hazards to avoid during future ring crossings.

This forum digests new data so fast that by the time the press release shows up its already moved on to the next adventure.

Absolutely! Anyway, thanks to improved quality of official released images, I made a new version of the shadow pictures, now clearly showing also Enceladus shadow projected throug itself material!

Sorry, but I can't resist:

Click to view attachment

My apologies to SigurRosFan

Ian.

Thanks Ian!

I think you might be on to something

http://www.jpl.nasa.gov/news/news.cfm?release=2006-110

Doug

As Phil has pointed out, the H ring must have a very low optical depth. If you take a close look at Ian's above diagram (the one that shows the "panoramic view" with a longer-exposed inset) you can see that the H Ring is barely visible outside of the inset. The other rings are all clearly visible, though -- including parts of the D Ring that contain hardly any material at all.

Now comes the really fun part: figuring out what kind of orbit a particle in the H Ring follows. One possibility would be horseshoe orbits -- but, if that were true, the angular amplitude of the horsehoe of an H-Ring particle would have to be time-dependent, to accomodate the motions of Janus and Epimetheus within their mutual horseshoe! Since Janus and Epimetheus can approach each other to within about 5.5 degrees, I'm guessing any such "nested horseshoe" orbit for an H-Ring particle would be unstsable. Anyways, a fun project for someone in orbital dynamics.