Just 17 hrs and 8 hours from closest approach. Current view.

http://space.jpl.nasa.gov/


Last sim is with about 15 min to closest approach in about 7hr 45 min,

.....what a view!!!!!

Partial eclipse of Rhea by Dione 16 Hrs before closest approach. Hope the real thing run according to plan

There is a thred already started.

Did not realise, maybe they could be moved over.

Still no news on the success of the flyby and no raw images?
I'm starting to wonder if they're cooking up another unpleasant surprise for us?
Previous experience seems to show that no news is bad news...

The first few images are up. Check this one out!

Wow, what an amazing eclipse image

Edit: I could not resist and made a quicky GIF movie. Some frames from the begining of the sequence are not available yet.

Here's the latest Dione image, processed to reveal details evenly across the surface, which has the effect of smoothing the global brightness gradient (high pass filter, but with edge artifacts removed):

Click to view attachment

It shows the smooth plains area at right very nicely. This is the best candidate for cryovolcanic resurfacing anywhere in these icy satelites except Enceladus.

Phil

Everything going fine!

I'd like to nomintate the entire Rhea eclipse sequence as the best series of images in the mission so far.

I rate this image as my personal favorite.

Nice one here:

Dione



Like fractured glass--interesting set of lines crossing at a point.

That's from a few flybys ago but still nice.

Cassandra is a strange feature...

Everyone's been referring to this Dione/Rhea "line-up" as an "eclipse", which got me thinking about actual eclipses.

Roundabout 2009 or so, when Saturn's rings go edge-on as seen from Earth, the moons will actually be able to eclipse one another. I haven't done the calculations, but my guess is that Rhea's umbra should be able to cover up all the other inner moons entirely. This leads to some interesting possibilities -- it'll be neat to see Enceladus, Tethys or Dione illuminated _only_ by Saturnshine!

Also, eclipses of Enceladus by Tethys, Dione and Rhea would be perfect times to look for evidence of Enceladan volcanism. No dazzling moon to spoil your long time exposure!

Just as interesting will be eclipses of the inner moons by Titan. Will its upper atmosphere "redden" them the way Earth's atmosphere reddens our Moon?

You wouldn't necessarily need another moon to eclipse Enceladus to get a good long exposure for plume searches. An eclipse by Saturn would do the trick.

Hmmm. I hadn't thought of that. Would an eclipse by Saturn completely darken Enceladus while leaving some of the space around it in bright sunlight? I'm thinking of Saturn's atmosphere; there's gotta be some "fuzzing" there.

Anyways, I went forward in time (on the Solar System Simulator) to see if it was possible to find a moon-moon eclipse just by searching for them around the time of solar ring-plane crossing. I did find one: Dione eclipses Enceladus on August 10th, 2009 at 07:58:00 UTC. The Simulator doesn't seem to render Dione's shadow on Enceladus; you have to select a view of Dione seen from Enceladus to see that it does indeed happen.

(On second thought, this eclipse stuff is kind of off topic for this thread. If anyone wants to follow this further, we ought to create a new thread for it.)

But if a moon is eclipsed by saturn there is no saturnshine is there? Or does the rings scatter enough light to light the moons? Aren't the rings just a thin line in most moons "skies"?

/Mattias

I attempted to find the Dione-Enceladus eclipse mentioned by Rob using Celestia. I was surprised and delighted to find that it worked, and that moon-on-moon eclipses are reproduced perfectly by Celestia.

If you have Celestia installed, copying and pasting the following CEL link into your browser should call up the eclipse.

cel://Follow/Sol:Saturn:Enceladus/2009-08-10T07:58:29.88379?x=ADCSaOv6Z7cqDA&y=ykRgw5vhppUF&z=VVD68TtOz2Lv/////////w&ow=0.739472&ox=0.014608&oy=-0.672168&oz=0.034034&track=Sol:Saturn:Enceladus&select=Sol:Saturn:Enceladus&fov=0.104774&ts=1.000000&ltd=0&rf=38835&lm=4

Works like a charm. :-)

Look at these peeeetty images!
http://saturn.jpl.nasa.gov/multimedia/imag...5/N00040986.jpg
and this too (Teti):
http://saturn.jpl.nasa.gov/multimedia/imag...5/N00040990.jpg

Mother Nature is without doubt the greatest artist of all.


Doug

It took me only a few minutes of searching to find that eclipse, and I did it completely through trial and error. There must be tons of other moon-moon eclipses around that time in 2009.

Perhaps you can introduce me to this 'Mother Nature,' I have a few requests...

Just been browsing the Raw Images archive of the latest images of Dione and I found this item.

There are two more 'white-out' images on the database at the moment (see here and here).

Does anyone have any idea what was being imaged/might have caused this?

Here's hoping that nothing has happened to the camera.

They are here!!!!!

Check this one out - http://saturn.jpl.nasa.gov/multimedia/imag...5/W00011114.jpg

Telesto looks smooth!

It is in a set with images like this one. I think it an image of Dione in Saturnshine, only it missed and got the sunlit size, and therefore is overexposed.

Here is an pseudo-true-color image of the crescent edge of Dione, combined from raw images through the IR1, GRN, and UV3 filters. Not a very colorful place, but interesting.

Click to view attachment

I prefer this one
http://saturn.jpl.nasa.gov/multimedia/imag...5/N00041260.jpg
the CL images like this shows a diaphanous surface... really amazing!

I tried to combine some of the raw images of Dione in front of Saturn, but as you can see the movement is too much: you can stack the Dione images or the Saturn one, but the other comes out badly out of whack.

Click to view attachmentClick to view attachment

So here's a cut-and-paste job approximating the color view.

Click to view attachment

All images are stacked from raw, using clear, green, and violet filters. I played a little with the color balance on saturn subtracting some of the green and violet from the clear image used for the red.

The image you've linked to is, well... all I can do is quote Dave Scott, upon his arrival into lunar orbit:

"This is profound, let me tell ya."

Now THIS is what alien planets ought to look like!

-the other Doug

Now, that's an icy moon! Most of these outer-planet moons with crusts made primarily of ice look more like rock to the untrained eye. They obviously have ground-up regoliths and such, and the whole thing gives the same impression as a rocky landscape.

But this looks like ice! Gleaming, very pure ice. The impact and tectonic features look glassy, and as if things have fractured along plane lines (as they ought to in ice).

This encounter is providing some very impressive images!

-the other Doug

Here is a merge on the super-pretty Dione in front of Saturn with Rings picture. I'm sure within a day or two the Cassini team will have this done a bit better, but for now enjoy!
Click to view attachment

Spectacular!

What do you make of this image?


Tom Tamlyn

Some of those holes are not impact craters!!

A crop from the Dione images:

Another:



So are the bright, sinuous features cliffs where some kind of faulting has occurred?

Few might side images. I was expecting more.

I think we may see more. Remember the Telesto flyby was less than three hours after Dione, so it had to turn away. But it may have turned back...we will see in the next release.

That picture looks like a scale model, not a real moon.

*Please note that I do not think it is a scale model (gasp, you mean it's not to scale!?), but merely that it resembles one in this particular picture.

Here's a higher resolution image of the same region: http://saturn.jpl.nasa.gov/multimedia/imag...eiImageID=51679

Here is a mosaic of Dione's limb:
Click to view attachment

Wow, in that mosaic its clear that long fault runs down the whole moon. Great mosaic!

Another oblique view showing more of those faults:

Outstanding images! I'm really glad my pessimistic thoughts a while back turned out to be all wrong. This encounter IMHO turned out to be one of the most exciting ones in terms of viewing geometry. Really terrific views with Saturn in the back and that rough crescent landscape in the above pic (which actually reminds me of Europa in "2010" when they send a probe in for a closer look )

If this doesn't go a long way, PR-wise, I don't know what will

I have absolutely no words congratulation!

This has got to be (along with the titan surface images) the single most stunning image produced thus far by the mission. It is like you're standing on the surface!!

When I compare these two moons, some major points jump out at me:

Enceladas -> Dione
- One is more active than the other.
- One is active now, the other appears to have been active much earlier and then stopped.
- One is about half the size of the other
- One is closer to it's parent than the other
- One appears to have liquid underneath the surface, occasionally venting. The other does not appear to vent, but may have liguid beneath the surface (well... ok, that one is a stretch, but who knows what we may later find out about Dione?)

Then I think of another pair of moons we are familiar with:

Europa -> Ganymede


Does anyone else feel there is a similarity here?

RAW Preview images are up at the ciclops website http://ciclops.org

Another oblique crop:

Funny that you mention that, I was just thinking that some of the Dione images remind me a bit of Ganymede. It may be just because a lot of these images have a darkish (slightly underexposed) colour to them.