Just 7 days until the next Enceladus encounter.

CICLOPS Rev 88 Looking Ahead should appear here before the encounter.

Cassini Enceladus 088EN Mission Description shold appear here soon.

We get to fly through the south polar jets again.

-Floyd

Mission description portion is now up.

Link

Covers both encounters this month.

Edit October 8th: Two entries in looking ahead.

General

Special

I must confess that I haven't gotten excited about the Saturn encounters in advance, but this little world has really captured my interest. I can't wait for this one.

and the timeline has been included into the realtime simulation at http://www.dmuller.net/cassini

Ciclops Looking Ahead for Rev 88 is now up...

http://ciclops.org/view/5293/Enceladus_Rev_88_Flyby

nice..

Craig

Sorry folks ... looks like the Looking ahead was already posted....

Still nice!!!

Craig

I created a simulation of this encounter using an experimental ground track feature in Celestia:

http://www.youtube.com/watch?v=R20d8sJae4E

The trajectory is marked off in three second intervals. What's amazing to me is how damned fast the encounter is: the video is in real time. I'm so used to thinking spacecraft flybys as fairly leisurely affairs, with ample time to aim cameras and other instruments. But this is barnstorming! I'm even more impressed now with the success of the 'skeet shoot' technique used in the August encounter. Bravo, Cassini team!

(The video looks much better without YouTube's compression: 2.0M AVI, DivX: http://www.shatters.net/~claurel/celestia/...dus-9oct08.avi)

--Chris

Looks like it's about time for me to update my version of Celestia. Nice work, Chris!

Raw images are starting to come in now.

Actual motion blur - love it http://saturn.jpl.nasa.gov/multimedia/imag...4/N00121207.jpg

I hate those truncated lines, especially how they totally trash binned frames. There HAD to be a better lossless (LOL - "lossless") algorithm than that.

Yeah, I know the cameras were designed in the mid-90s...

Everything went great for the Cosmic Dust Analyzer (CDA) during this flyby. We got good data during the entire flyby—before, during and after closest approach. We recorded mass spectra even in the deep plume with no data gaps as far as I can see.

The High Rate Data rate count profile shows pronounced peaks at the time we traversed the jets. This data is key for pinning down the structure of the dust jets.

The source of information is Cassini Team Blog (Sascha Kempf).

They are more of a problem in the jpegs. In the real raw images, they are the only thing that registered as absolute black before calibration, so I can deinterlace the affected areas without damaging the non-interlaced sections. The effects of the jpeging make this impossible without damaging shadowy areas as well.

They introduce pretty ugly aliasing by their very presence, though. You can't get rid of that even with calibrated images - it's not simply a lower vertical resolution, the sampling completely misses alternate lines, which is not the case for example with normal 2x2 binning.

I can't shake the feeling the algorithm would work much better if the compressor didn't just rely on the previous pixel for prediction, but also on the neighbors from line above, similar to what PNG does. It would improve compression ratios and probably greatly alleviate the truncation problem with no ill-effects on image quality. The downsides would be lower transmission error resilience and slightly greater processing cost, but seeing how the camera system is very limited even now in the telemetry rate it can send, achieving greater compression might actually speed up the whole process.

Back on topic... when are the rest of the images scheduled to come down?

I realize that. I'm just saying it is even worse with the jpegs, because it is next to impossible to remove without damaging the areas that are not interlaced.

The 2x2 binning makes it worse, particularly when you are mosaicking these images, as I automatically have to enlarge the images by 2x, which just magnifies the aliasing.

Maybe I wasn't completely clear above: I meant the truncation on full frames could in certain cases make the result turn out worse than 2x2 binned, non-truncated frames.

2x2 binned AND truncated frames indeed are the worst possible case.

There are various new images like this one:

http://saturn.jpl.nasa.gov/multimedia/imag...iImageID=170225

It almost looks like a side on-view of a vent spewing material into space, but the caption says the camera is pointing at Saturn. Is that a limb on the far left, and then what is the much brighter "limb" on the right? Wishful thinking says it is a overexposed picture of Enceladus, showing a water geyser in action. But perhaps it is just some internal calibration (since the geometry does not seem to be changing) instead...?

Airbag

The (Saturn's) nightside limb is on the left, the bright stuff on the right is the terminator region. The fuzzy splotch in the middle is an internal reflection in the optics.

it also says SATURN is the target there. if it were spewing materials, wouldn't it say ENCELADUS?

Looks like some new territory in this image:

http://saturn.jpl.nasa.gov/multimedia/imag...ails170298.html

There is also a partial set of the most recent images on the CICLOPS page (some of which aren't on the raw page). These may be of better quality:

http://ciclops.org/view_event/92/Enceladus_Flyby_Raw_Preview

I cannot believe that I'm defending this algorithm, but it has some good features that were probably why it was chosen in the first place. Each compressed two-line block occupies a fixed size, therefore not only the total size of the compressed image is fixed and known in advance (which is necessary for memory budgeting), but the beginning and end of each block is known too. Therefore, in case of data corruption during transmission, when some lines are missed, it is possible to reconstruct the rest of the image. If the compression had used data points above each pixel, then successive two line blocks would have been dependent on each other and the reconstructions wouldn't work.

have we seen all the images then? or is it just the weekend holding things up?

All the images are on the ground, at least from ENCELCA001, so I am not sure what is happening with the JPL raw images page. Maybe they have issues with their real time scripts?

There are some new images of Enceladus up on the Cassini website.

Click to view attachment

Lol at today's APOD image: http://antwrp.gsfc.nasa.gov/apod/astropix.html.

If the right hand side of the image doesn't showcase artifacts of line truncation, nothing does. Leave it to APOD editors to overdo it with sharpening.
Almost looks like a VIMS cube and not ISS frame (no disrespect to the VIMS instrument intended!).

Gordan, I don't think they actually do anything to the images. It may well have been given to them in that state.

I don't mean the image the root page actually links to, I mean the magnified image that links to the actual product. I've noticed they have a tendency to overkill with sharpening on the page with the description, but once you click through you get to the original. Note in this case the product is both lower resolution and doesn't show that much aliasing as it's the original deinterlaced version.

Here is a higher resolution version of the October 14 APOD image.
Click to view attachment

there`s a nice little raw image sequence of the october 9th flyby of enceladus as well.
couldn't resist.

Dirk,

Click to view attachment

The above animation gives the feel of really riding along with Cassini.

Here's a test map put together with just a bit of coverage from the October 9 flyby. I hope to extend that coverage next time. This also has more color information brought in for a range of longitudes near the south pole.

Click to view attachment

Steve

That Enceladus map looks great! Thanks for posting this.

Those images of Enceladus are simply breathtaking. The level of detail in them is fantastic.

Have any images yet been taken of the ice jets that do not include an edge on view of an overxposed Enceladus? Can the jets be seen from passing almost overhead?

To what minimum resolution is most of Enceladus mapped now?

Yes, it's pretty interesting how the available images are filling in more and more at a higher resolution. Typical distances for the higher resolution images range from 15000-25000km so I'd have to figure out how many meters per pixel that is (with also a slight consideration of the NAC PSF). Another approach is to note that the map scale at the equator is 194 meters/pixel. An updated full resolution 8K map made on 10/23 can be seen at this link:

http://laps.noaa.gov/albers/sos/sos.html#ENCELADUS

A 39% resolution version just fitting the 1MB size limit is attached below:

Click to view attachment:

I'm continuing to work on image prioritization and navigation in areas such as Cashmere Sulci and Mosul Sulci. Navigation and color can be improved in other areas as well.

I think it has been mentioned that the August flyby has some pretty close up images where the jets are from nearly overhead, however they wouldn't be directly visible.

That's the latest,

Steve

Curious, did I miss something?

I was really excited over this Enceladus flyby, but it doesn't seem that any one else was, at least not as much as the August flyby. Also, there doesn't seem to be as many pictures available from this most recent one. Was that intentional?

This flyby was all about plasma/fields/waves/particles etc

Doug

The other issue is that the various instrument teams are lumping these two flybys together. So rather than do two press releases, one for each flyby, they are probably going to do one.