With its second to last swing by Titan the curtain has now opened on Cassini's final act. What wonders will we see in the rings?

Rev 251-253, Nov 30 - Dec 22, News Room Looking Ahead Link

Should be exciting and starts tomorrow, November 30.

Any resources out there folks can suggest for monitoring in near-real time?

Yea! Right here : ))

Eyes on the Solar System has a Cassini module, if that is what you were looking for.

First ring-crossing complete.

https://spacefellowship.com/news/art49608/c...ing-plunge.html

Cassini got a good look at Enceladus just a couple of days before embarking on the ring-dive orbits:


2016-11-27 --- ENCELADUS QUATRO UNCROPPED


2016-11-27 --- ENCELADUS QUATRO

Now it looks like we can see clouds on the border of Saturn's north polar region (NPR) casting shadows!

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Quick question: When Cassini's periapsis is between the planet and rings, would we be able to get a measurement of the planet's core mass (like Juno is doing at Jupiter)?

IIRC this is one of the scientific objectives of this mission phase

Could Cassini see dust particulate falling above the ring plane into the upper atmosphere?

I imagine Saturn having a nightly show of shooting stars on the night side.

Yes, this is one of the main grand finale objectives, but not achievable until Cassini makes the last major orbit amendment in April next year and begins those revolutions which take it between the inner edge of the D-ring and the planet itself. This provides the opportunity to separate out the mass of the planet and the rings themselves,

i am updating the Cassini Celesta SPICE files on celestailmatters
date time span from jan 2015 to april 2017

this is using the spice orbits !!!!! in celestia and NOT!!! the default
http://forum.celestialmatters.org/viewforum.php?f=18

as of right now cassini is here

The G-ring as seen by ISS on the 4th:

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One key difference between Saturn and Jupiter is that Saturn has a much greater scale height, stretching out the vertical structure of the atmosphere. That's a huge advantage for visual recognition of relief in Saturn's clouds.

Nice "propeller" caught by Cassini:

https://saturn.jpl.nasa.gov/raw_images/403447/

That is a nice one. Looks like it's in the process of 'clearing it's neighbourhood' too....

Hey there, Daphnis!

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That is arguably one of the most stunning images in the history of space exploration. Incredible, Ian.

Holy Crud! Awesome!

P

Great to see the little blighter up close.
It appears that the orbital dynamics are still very tricky to pin down definitively - it falls outside the FOV in most of the images. No complaints though!

So much to unpack in that image. Bizarre shape (are those ridges?) and those 'streamers'? And what is that shadow on the sunlit side? Surely not something popping up from the surface, right? Or is it even a shadow, or some sort of dark material on the surface?

Such a 'grainy' texture to the rings as well, are we on the verge of resolving the largest of the individual particles (maybe those specks on the edges of the gap?). What sort of resolution is it?

I know we won't get views like this for a long time after September, but I can't even fathom where one would get started on designing a dedicated ring mission...

Amazing image! I have made an enlarged version with a clearer view of the ridges on the surface. I think they are real ridges. The shadow looks like a deep hollow.

Phil

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Oh and look at this one! Wall of ice pillars emerging above ring plane..

Unfortunately I think that Cassini is a long way away from resolving the ring particles here, and won't be capable during the mission of achieving that.
For context the Keeler gap is ~40km wide, and Daphnis is 8km along its longest axis. I think the grainy texture is clumping of smaller ring particles.

This feels like we're going back to Kepler and Newton working out planetary dynamics. Do gravity plus Newtonian physics alone explain all of this wackiness? Amazing. The math here may turn out to be more like the dynamics of galaxies rather than anything else we've seen in the solar system.

I thought that looked familiar

http://www.fantastic-plastic.com/NXClassPodSide.jpg

I have looked at almost every PDS-released image obtained by Cassini (the vast majority I looked at for less than a second though). This is one of the most spectacular Cassini images I have seen (and there are thousands of highly spectacular Cassini images out there).

Interesting that Daphnis shows little or no evidence of an equatorial 'girdle' like Atlas and Pan. I believe it's rotation is synchronous (as are theirs) so there must be another reason that it doesn't accumulate ring constituent particles in the same way as those moons?

Endlessly fascinating this mission.

At 250 km above the martian surface, MRO has a resolution of about 35 cm, so in terms of sheer resolving power, what you suggest is very modest. However, the quality of the science depends on the nature of the target. Perhaps the ring particles in such a view of, say, the B ring, would be against a backdrop of other, similar ring particles, making the image blandly or chaotically uninterpretable. The edges of the rings seems to be a better place for observations; even in the B ring, maybe stereo imaging would provide clarity. Knowing what we would see would depend upon knowing the nature of the ring particles, which is the very thing we'd be looking to find out. It seems, though, that high-detail visual imaging of the ring particles is possible, at least in certain geometries.

ADMIN NOTE: Moved 8 posts regarding possible future ring missions to a dedicated thread for that topic.

Wow, check out Epimetheus here. This just in!

http://saturnraw.jpl.nasa.gov/multimedia/i...7/N00275739.jpg

People pondering the origin of the grooves of Phobos will need to think about this.

Phil

Mosaic of two images of Epimetheus:
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The same grooves on an object about 5 x the radius of Phobos, and made of ice rather than rock... how bizarre.

New Mimas Saturnshine images are down as well!

It looks that Epimetheus is another body in the Solar System with dune-like features on its surface (look at central lower part of this image).

Good point Phil - the two look visually analogous. I wonder if it's anything to do with these small bodies being at or near the Roche limit?

The Mimas images are beautiful too - this phase angle really shows up the fact that Mimas is largely water ice rather than 'rock'

Epimetheus really looks like two parts Phobos (the grooves and shape), one part Eros (the bicolored slopes).

It feels like we're getting close to something like a phase-state diagram of small bodies. Something like escape velocity on one axis and whatever else explains the varied nature of these places on the other axis/axes. It's remarkable how varied they are, but we're seeing repetitions of each phenomenon; the causes should start to become clearer.

Amazing views.

Looks like there may be a few collapse pits in addition to craters. Reminds me a bit of a cometary surface, actually.

Some flyby gifs:

Color image of Daphnis from 2017-02-06 21:05 (UTC)

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Some very nice images of Epimetheus recently. Here are two showing lots of grooves. I have brightened the area illuminated by Saturn to hint at what the raw data will show us when it arrives in PDS. one image is almost entirely lit by Saturn rather than the Sun.

Phil

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Some great Mimas closeups in the newest raw images! Looking forward to colour composites from you excellent lot.

Here's a quick RGB composite from yours truly, with some cleaning up of the artifact, although it's still not perfect:

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That's no space station, it's one heavily cratered moon!

Incredible new views of Pan, and its razor-thin equatorial bulge!

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North is to the upper-right.

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Staring face-on at the north pole.

Edit: Thanks to Dr. Phil for pointing out my north/south confusion.

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Medium range view, showing the full extent of the Encke Division.

Another medium range view, bore-sighted on the moon's north pole:

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Edit: Thanks to Dr. Phil for pointing out my north/south confusion.

Astonishing. Looks like a cutaway view of a nut covered in chocolate. Accreted ring material around the equator, I presume.

Fantastic images... and one little correction. As you say, Ian, north is to the upper right in the first view you posted, so the partially illuminated bulge at lower left is the southern hemisphere. The other views show the northern hemisphere, not the southern. Pan has the same seasons as Saturn, and now the north is more fully illuminated.

Phil

Lots of cracks or faults, is it experiencing a lot of stress?

On another note, it looks as if the bulge might not be much less cratered than the main body.

It looks like a miniature version of Saturn.... or a pork tenderloin sandwich.

amazing! Rings must be quiet thin (tens of meters) and with a stable vertical position relative to Pan.