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Posted by: alan Jun 3 2005, 07:27 PM

Solar system simulator shows an encouter under 500,000 km on June 6. Will there be a good view of the south pole on this pass?

Posted by: volcanopele Jun 3 2005, 08:06 PM

Funny you should ask:

http://volcanopele.blogspot.com/2005/06/rev09-non-targeted-encounters.html

The answer is yes, we will, weather-permitting, get a good look at the south polar region.

Posted by: Decepticon Jun 3 2005, 10:57 PM

http://space.jpl.nasa.gov/cgi-bin/wspace?tbody=606&vbody=-82&month=6&day=6&year=2005&hour=20&minute=00&rfov=30&fovmul=-1&bfov=30&porbs=1&brite=1

Posted by: volcanopele Jun 5 2005, 06:31 PM

Images from yesterday are on the ground and are showing up as "existing" on the JPL Raw images page, but the images themselves aren't there. We have two more image sequences scheduled for today and tomorrow so higher resolution stuff to come.

Images so far are looking good though...

Posted by: tedstryk Jun 6 2005, 01:27 PM

They are posted! Check out this one - it is part of a great multispectral image set of Titan!

Posted by: dilo Jun 7 2005, 06:35 AM

Let's start with a approach animation:
http://img151.echo.cx/img151/155/approach4ry.gif
then a false color enhanced image using MT3,B3 and UV filters:
http://img295.echo.cx/my.php?image=titanm3b3uv5nj.jpg
notice the famous "Odd Spot" near the center of image...

Posted by: edstrick Jun 7 2005, 07:30 AM

I grabbed the last of the Rev 009 Titan full frame pics with the best surface visibility from the raw images site and ran a couple bandpass-filter enhancements on it to bring out details.

Attached are 3 files, the original raw image, as usual with Titan, enough to make me want to clean my glasses.

The XXXX_e.jpg enhancement used a 81 pixel max filter size and an anlysis box covering the disk but not much of the limb to bring out fine scale disk details. Of course, it brings out in horrific detail the JPG artifacts in the online image, but not much I can do about that. These views will clearly provide the best overall view of Xanthe we've gotten so far. The "Smile" which is the southern boundary of the 5 micrometer wavelength redspot is clearly only a half circle, with no trace of continuity to the north (north is at about 55:00 clock angle).

The XXXX_e2.jpg image was enhanced with a 27 pixel max filter size and an analysis box including the entire limb. Much interesting detail is visible in limb haze layering. The north polar haze cap is beyond the limb at 5:00 clock angle, while a detached haze layer seems to be present from the equator (2:00 to 6:00) and somewhat north, but not at mid northern limb latitudes. This layer disappears at 1:00 and 7:00, though a sharp lower limb haze is visible at 7:00 which disappears at 8:00 clock angle. Further south, at 9:00 and 12:00 clock angles, a detached limb haze again becomes visible, and it TAPERS southward, becomming more visibly detached from the lower limb haze or whatever, disappearing in the 10:00 to 11:00 clock angle of the image at the southernmost latitudes.

Lot of structure in the limb hazes with latitude that will bear analysis.

Posted by: dvandorn Jun 7 2005, 08:25 AM

Looks like an impact crater that's been half-covered (or half-erased) by some process(es) yet unknown. But the half that remains really has the classic form of a crater.

Of course, that's just what it looks like to me. Could be a bunch of things. But impacts are one of the few ways (and by far and away the most common way) in which nature makes such big circular features, and the half that we see looks like a perfect half-circle.

Now, if it *is* an impact crater, and the northern half has bene submerged or overridden by some resurfacing process, maybe it's the resurfacing process, and not the remnant crater form, that's causing the redspot. The crater wall might just be controlling the extent of the redspot "condition" geographically -- for example, if there's a cryovolcanic "flow" encroaching into a crater, gasses emitted at the flow front could continue along the same direction, hit the far crater wall, and be ducted upwards into an upwelling that results in the redspot condition we're seeing.

-the other Doug

Posted by: edstrick Jun 7 2005, 09:26 AM

The sharpness and high contrast of the Smile with it's surroundings suggests youngness. But then it totally stops and what appears entirely unrelated light and dark markings cover where it' s northern half would be. I have a strong feeling ... mentally putting odds of 70:30 on it's NOT being a crater. We just can't tell yet.

Posted by: Decepticon Jun 7 2005, 01:19 PM

Wow ! Lots more.

http://saturn1.jpl.nasa.gov/multimedia/images/raw/raw-images-list.cfm?browseLatest=0&cacheQ=0&storedQ=0

Posted by: volcanopele Jun 7 2005, 03:32 PM

Very nice! Looks like a pin-wheel at the south pole.

Posted by: tedstryk Jun 7 2005, 03:57 PM

Looks like some terminator shadows, whether in the clouds or on the surface.
http://saturn1.jpl.nasa.gov/multimedia/images/raw/casJPGFullS11/W00007189.jpg
http://saturn1.jpl.nasa.gov/multimedia/images/raw/casJPGFullS11/N00035096.jpg

Posted by: volcanopele Jun 7 2005, 04:10 PM

I think those are just surface markings. Those we can match up to T0 features appear to be consistent, despite the change in illumination angle.

Posted by: tedstryk Jun 7 2005, 04:22 PM

Here is an enhancement....I can't wait to see a non-jpeged processing of this image and those like it!

Posted by: volcanopele Jun 7 2005, 04:36 PM

I'm working on these as I type

Posted by: Sunspot Jun 7 2005, 05:07 PM

WOW....is that dark "blob" real or an artefact of the imaging sytem?

Posted by: alan Jun 7 2005, 05:08 PM

Whats the smooth edged dark area on the right side of tedstryk's image? Could it be a lake?
http://s05.imagehost.org/view.php?image=/1181/N00035096p.jpg

Posted by: volcanopele Jun 7 2005, 05:12 PM

Maybe.....

Posted by: Sunspot Jun 7 2005, 05:36 PM

That exciting eh?

Posted by: JRehling Jun 7 2005, 05:38 PM

Great work... simple work, I guess, on an awesome image.

My sense is, with this image we've found our lakes, with verification coming after we get an opportunity to scan these with RADAR and/or align them for specular glints. If the lakes are there long enough for such a flyover (at the start of the extended mission?) to take place.

Titan's got long seasons. The observations so far are copacetic with this: The summer hemisphere sees sporadic methane clouds, most concentrated at the summer pole, and sometimes making a ring there. These clouds somehow lead to broader darkening of the overlying hazes. The clouds rain or mist down to the surface, wetting the summer pole and creating standing bodies of liquid and feeding seasonal systems that roughly flow equatorwards. That same pole may become dry during its autumn/winter.

The most exciting possibility would be if there is a winter ice cap lurking in the dark, that melts to release massive global floods as the equinox approaches, flooding the equatorial dark areas, which currently seem to be dry or damp at best, but to have endured floods in the past. If there is a seasonal cycle, then a new temporary ocean is a few years away. But, it may also turn out to be much longer, even an eon, since those dark areas were actually wet.

This image might well go down in history as a discovery/prediscovery image of great import.

Posted by: dvandorn Jun 7 2005, 05:46 PM

I really think many of these issues would be easier to resolve if we could get RADAR imaging of some of these areas, especially the polar regions and the area of the "smile". And, of course, the Huygens landing site.

Is there any source that can give us an idea of the planned RADAR coverage areas on Titan during the primary mission? I know it's impossible to say what might be engineered for the extended mission(s), but can anyone tell us what parts of Titan will definitely be RADAR-imaged?

-the other Doug

Posted by: gpurcell Jun 7 2005, 05:46 PM

Check it out, there is also what looks almost like a cloud casting a shadow about 10 o'clock relative to the lake!

Posted by: um3k Jun 7 2005, 06:02 PM

If you're talking about what I think you're talking about, then it is most definitely not a shadow. Here's a hint: The light is coming from the bottom of the image.

Posted by: volcanopele Jun 7 2005, 06:46 PM

It is very intriguing but we will need RADAR or a specular point analysis to prove the case. Nevertheless, this is the first feature I feel comfortable calling a "possible lake".

Posted by: dvandorn Jun 7 2005, 06:50 PM

Careful, though -- it could also be an empty lakebed filled with the same sort of "mud" that Huygens landed on. It's hard to say.

Will RADAR reflect off the surface of an ethane or methane lake, or will it penetrate right to the solid icy surface underneath? In other words, will a RADAR pass tell us if that depression is filled with liquid, or not?

-the other Doug

Posted by: OWW Jun 7 2005, 07:03 PM

Ice caldera anyone?

http://photojournal.jpl.nasa.gov/catalog/PIA02566

Shape is awfully similar.

Posted by: volcanopele Jun 7 2005, 07:07 PM

or lake bed...yes...

No, in all honesty, this is the first feature I have seen that at least morphologically fits what I would expect a lake to look like in our images on Titan. Doesn't mean it is, and we will need other evidence to either support or refute that theory, but it is intriguing.

If it is a lake, RADAR would see the lake as a VERY smooth surface, if the lake is deep enough. If it is dry, it is possible that the pebbles and sediment characteristic of the Huygens landing site would make it appear bright (remember that very bright area in the T3 swath?). However if the lake is only a few meters deep, it is possible a radar beam would pass right through, making it look the same as if it were dry. We could also look for a specular point, but it is too far to the west for that on this pass. Not sure if we get another look.

As for a caldera, I would like to see such a feature in RADAR before we start going there in ISS images. not that I wouldn't be thrilled to find one on Titan, but we should be cautious. I should probably say the same for a lake, but give n what we know about Titan and recent south polar conditions, a lake seem more plausible.

Posted by: tedstryk Jun 7 2005, 07:11 PM

Did VIMS observer this area on this pass?

Posted by: volcanopele Jun 7 2005, 07:22 PM

Possibly, but their resolution would have been WAY too low to resolve this feature

Posted by: tedstryk Jun 7 2005, 08:21 PM

Yes, but if it was a hotspot, I figured it might appear as an unresolved bright spot.

Posted by: Decepticon Jun 7 2005, 09:13 PM

I'm very impressed with this non targeted flyby.

I didn't expect so many pictures.



VP do you know if there are any more NT for titan for this year?

Posted by: volcanopele Jun 7 2005, 09:32 PM

None that I know of. though this is the only non-targeted encounter that has been given importance since it is really our last good look of the south polar region for the next 25 years or so, though RADAR will get a couple of looks, just not of "Peanut Lake"

Posted by: edstrick Jun 8 2005, 06:52 AM

Bandpass-filter enhancements of two pairs of 2/3 disk images, and 2 "best" haze penetration images from the closest coverage of the south polar region. Peanut-"lake" is certainly interesting. I've saturated the darker parts black in the enhancement, but I couldn't see much of anything there with softer contrast stretches.

Lot of variation in the cloud pattern between the two closest images. There's a lot of low contrast cloud above the main mass, closer to the termniator, varying between the frames, and some scraps of cloud near the peanut at 11 and 10:00 clock angle and another at 8:00 from the peanut.

Posted by: Phil Stooke Jun 8 2005, 01:23 PM

South pole of Titan... I've stacked four frames and merged them to reduce artifacts and noise. Then four different versions of the composite were processed in different ways (different contrast enhancements, different high pass filters), and all four merged together.

It's very interesting to compare this with the two T0 mosaics... I have a hard time matching this to those... maybe we will be hearing more about this.

Phil

Posted by: Phil Stooke Jun 8 2005, 02:10 PM

Here are the two T0 mosaics... reduced size, and not as well processed. I hadn't figured out the processing as well back then. I don't think I've seen the left one of these two posted before.

Phil

Posted by: JRehling Jun 8 2005, 02:20 PM

Nice work. There's a bit of detail I saw on Jason's contrast-stretching version that I can't see on the band-passed versions: Especially, a very sinuous (Mississippilike) channel approaching the Peanut.

My overall sense of Titan's topography is that it has numerous local basins that can be filled with liquid to a considerable liquid without overflowing, but beyond that, reach the level of an outflow channel and let liquid flow out as well as in.
I think what we're seeing in this specific image is a bunch of marshes or channel systems (the dark splotches near the clouds) that have recently received rain fill; and, the local basin into which they drain: the peanut-shaped lake. This will endure for a short time before it dries, leaving some darkness (organic sediment, as in the Huygens foreground) in the channel areas and lake bottom.
I myself feel that it's better than chance that a methane cycle with temporary lakes follows the summer pole as the seasons unfold. The question is, does an equatorial flood take place, giving Titan seas, when the winter pole thaws out (if there is any cap there to thaw out)? Which depends upon whether or not the winter pole is 4 degrees K cooler than the Huygens site -- that's what it would take for methane to freeze out there. The northern polar area is certainly that cool at the level of the stratosphere. So the question comes down to: Can Titan's troposphere conduct heat from the lower latitudes to the [winter] polar troposphere, while doing this all "under" the cooler polar stratosphere? If so, wouldn't we get some tremendous weather? Whichever of the two exciting possibilities, it's all happening in the dark!