Mission description:

http://saturn.jpl.nasa.gov/files/20090708_...description.pdf

Ontario Lacus......... at last

The looking ahead article for Rev114 is now up:

http://ciclops.org/view/5701/Rev114

Glad to see that the ring propellers are getting more scrutiny this rev. Those things are intriguing; wonder how long-lived they can really be.

600 miles... that's close. I'm looking forward to this one.

What is the deal with "ring propellers"? That link says they're voids in the ring; so why are they called propellers?

The name propeller is a reference to the shape of the voids, which often look like the propellers of an airplane like a Cessna.

Another narrow-angle shot, very similar to this one:

Click to view attachment

Slightly higher phase, July 5.

Just one from a real feast of new images:

http://saturn.jpl.nasa.gov/multimedia/imag...1/N00138509.jpg

I look forward to seeing what people do with them when I get back from a short holiday.

Any sar news?

They likely JUST got the data this morning. Give them time to process it, turn it into an image we all can see.

Indeed!! Two interesting ones (including N00138509 the one you highlighted with the clouds) and N00138393 (a narrow angle shot of the possible mountain range) are featured in the animation below. The sequence ends with the beautiful VIMS imagery of the region. ? will SAR suggest mountains or not ?

Click to view attachment

Are they likely to release the image when it's processed?

I thought SAR on T58 would be one of the highlights of ALL the Titan flybys...

These things are unpredictable... sometimes it just has to be released right away, other times it might be saved for an upcoming conference presentation or other special event. Meanwhile there are things happening all oer the solar system to keep us busy!

Phil

Hmmm i hope that isn't the case here....

Based on the most recent CHARM presentations http://saturn.jpl.nasa.gov/video/products/...aProductsCharm/ SAR imaging of the possible mountain ranges discussed in my post # 11 above may not happen in the extended mission.
The planned radar passes are shown on the Titan map and appear to miss the location of the presumed mountain range (except for a small swath whose label I can't quite make out).
The presentations above can be viewed as pdf files and they are excellent summaries of the mission discoveries to date and the mission objectives for the current extended mission.

Thanks for the link TR. The three presentations were all v interesting summaries (Spilker's, Cuzzi's and Turtle's) and I thought that the standard of graphics/presentation ranked with the best that I have ever seen from NASA. The Skeet shoot pics (p27 et seq - on Turtle's) seem a bit enhanced from earlier pics but I would have liked scale bars as on P26. It still blows me away that they (forgotten the smart guy's name whose original idea it was) slewed the spacecraft round so accurately that they got such crystal sharp images!! Cutting edge indeed.

Well worth a look.

[quote name='HughFromAlice' date='Jul 29 2009, 10:14 PM' post='144039']
Thanks for the link TR.
The Skeet shoot pics (p27 et seq - on Turtle's) seem a bit enhanced from earlier pics but I would have liked scale bars as on P26. It still blows me away that they (forgotten the smart guy's name whose original idea it was) slewed the spacecraft round so accurately that they got such crystal sharp images!!



You're welcome HFA!
If you scroll down in the CHARM series you'll see the presentation on the Skeet shoot pics dated 11/25/2008. The names of the presenters are: Paul Helfenstein from the Imaging Team, John Spencer from the CIRS team and Sascha Kempf from the CDA team. I think the first person is the bloke who thought of and planned the skeet shoot imaging.

You've jogged my memory. It was!! http://www.planetary.org/blog/article/00001727/

Greetings from Cassini !
Latest Postcard from Cassini of Titan in between T58 and T59 flybys. Images taken with different filters (indicated above each photo) on July 12, 2009 and received on Earth July 13, 2009. Titan was approximately 2,200,000 kilometers away from the camera in each case.

Click to view attachment

Interesting article from New Scientist :

Largest Lake on Titan varies in height by only 3 millimetres

Sadly - or perhaps fortunately - Ontario is not the largest lake on Titan. Also, it may be flat at any one time, i.e. calm, but its level may vary seasonally by a lot more than millimeters. So, all in all, a pretty misleading headline. See:

http://adsabs.harvard.edu/abs/2009LPI....40.1990L

for the proper information.

That's by far the most concise & to the point abstract I've ever seen...

Here's the pdf file of the abstract:

So, with lower density rock (ice), less viscous fluid (?), lower gravity, and thicker air....

How much farther could you skip a rock on Titan?

The Mechanics of Rock Skipping

How much farther could you skip a rock on Titan?

Search me. However on earth the record to beat is 51 skips and 250 feet!
http://www.msnbc.msn.com/id/21070570/

Note that it's another one of Ralph's patented Haiku abstracts, if you count the syllables . . .

- Jason

Hai, ah so ne!

Planetary wonk, publishes major findings, condensed and striking!

This is clearly a question I should devote some effort towards considering, not least
since I have instrumented skipping stones with accelerometers etc.... as described in
my book 'Spinning Flight: Dynamics of Frisbees, Boomerangs, Samaras and Skipping
Stones'

Although there have been some neat analyses of the skipping process, the combined
aerodynamic-gyrodynamic-hydrodynamic problem of modeling an end-to-end stone
skip trajectory has not been satisfactorily modeled (e.g. as my book qualitatively notes,
the pitch-up aerodynamic moment and the pitch-down moment usually generated by
water impact at a positive angle of attack tend to make the spinning stone roll in
opposite directions)

Might be the viscosity and surface tension of Titan liquids affect the process in ways
that can only really be studied experimentally..

The last Cassini web site Titan press image released was taken with the narrow-angle camera on July 9, 2009 (T58) shows a small part of Senkyo on the trailing hemisphere. This area had not been imaged in high resolution until the last several flybys. One can appreciate how recent imaging has filled in the Titan map gaps by looking at the Celestia Titan surface map (now several years old) and comparing it with the latest ISS Titan map. The graphic below depicts this.

Click to view attachment

T58 RADAR swath (with Ontario Lacus).
Click to view attachment

Sweet! Nice deltas, and a neat volcanic-looking craterthing to the right of the lake.

T58 RADAR swath with Ontario Lacus and the surrounding area in higher resolution.
Click to view attachment

Ontario Lacus @ 128 pixel per degree, or about 350 m/pix. Constructed from T57 and T58 SAR plus PIA13172 (a piece of T65 SAR).

Interesting raised area with crater. Cryovolcanism? Pedestal crater?
Click to view attachment

Illumination is from below. So that is actually a depression, not a raised area. This feature is most likely a dried lakebed.

optical illusions ,fun,fun,fun
the ones i "see" all the time are the raised impact craters
blinking an inverted tone image helps
2 frame gif
Click to view attachment

ps that line better be a radar artifact

...with steep sides around the edges. However, that central darker spot in the largest bright area *might* be a slight depression infilled with different RADAR-reflecting properties. Damp muds, for example.

A four-frame VIMS animation showing the evolution of the lake specular point:
Click to view attachment
Magnified 5x using nearest neighbor interpolation to show the actual specular point pixel size. It's only visible at 5 microns, the green (4.67 microns) and blue (3.26 microns) channels aren't in methane windows, they were chosen merely so they wouldn't be overexposed in the longer exposure cubes.

Nice animation Gordan. Would the evolution of the glint depicted here tell us mostly about the lake extent, or also about expansion of the glint by wave action (or lack thereof)?

Pretty much lake extent only AIUI. The latest understanding appears to be that the lakes are very flat i.e. not much wind-driven wave action.

Thanks for the movie, ugordan. This is an elaboration ot third frame, compared to original...

The size is only telling you about the point-spread-function of the VIMS instrument, as it turns out -- not lake extent. The time evolution is telling you about the waves and whether the specular point is on land or liquid. My paper on this was just accepted, and I will post a version here as soon as it's up on the _Icarus_ website.

What the heck, here it is. It will be up on _Icarus_ in press soon.

- Jason

It is in press now, as of yesterday.

I'm behind the times, evidently. Thanks ISS Jason!

- VIMS Jason

Thanks for the paper, VIMS Jason. So, there's 14 speculars on T59 as well?

Must...animate...those...

Go for it! I look forward to seeing it!

But I have to warn you -- the T59 sequence is not nearly as impressive as the one from T58. Greater distance to Titan for the interesting parts leads to a much lower maximum intensity on the specular flux.

- Jason