The latest shots of Mezzoramia and environs are nice:
http://saturn.jpl.nasa.gov/multimedia/imag...7/N00131391.jpg
I'm not sure if that's a cloud streak on the left.

Yeah, those are clouds.

Huh? Are they even aligned E-W? Maybe I'm looking at something else...

Same image that Nigel posted, but gamma contrasted, rotated, and annotated view. N is roughly towards the top.

Click to view attachment


The cloud streaks are faint vertical in this image (at the end of the red arrows). (Hard to tell absolute orientation at these high latitudes, but I think they might be closer to N-S than E-W).

-Mike

Mike...

as always your work blows me away... I have to get a new ink cartridge and print head just to keep up with your Huygens
image products...

Are we not all just chomping at the bit to see how the weather changes come Equinox!!!! Will we start seeing clouds in the 'tropics'?

Craig

Exactly... did wind patterns change in the troposphere? Or is it the projection?

Before people start speculating too much, those streaks are E-W. They are just a tad close to the limb there.

From 'looking ahead' for 103 (and 104 is now there too):

"On Feb. 15, ISS will acquire several satellites observations. These include a nine-hour long observation of Titan where ISS will search for clouds and hopefully watch them move across the southern part of the sub-Saturn hemisphere. This distant observation will also provide an opportunity to look at Mezzoramia, a dark albedo region in Titan’s mid-Southern latitudes. Distance to Titan varies during this long observation between 1.2 and 1.37 million kilometers"

This suggests that there should be many more images like the one we've been discussing. Were they acquired?

Slightly OT, but is there a way to light up a lat/long grid on a planetary body in Celestia?
Also, is there a good surface feature (ISS) map of Titan add-on available for Celestia?

Custom overlays allow you to do this Mike : http://www.lepp.cornell.edu/~seb/celestia/...ison/grids.html

Version 1.6, currently in beta, provides support for various overlays, such as body axes, sun direction, and a lat/lon grid.

I have a custom add-on that includes a pair of nice Titan maps that I have been trying to get to more cleaned up state for public release.

Well, thanks for the tip. I installed it and now I can do lat/lon grids for everything but Titan.

However one can easily get a blank grid on a planet (say Mars) in Celestia, save it and using coordinates from an existing Titan map (say PIA02147), layer it on Titan images matching several locations using longitude and latitude. Such was done in the animation below. It helps to have the Titan raw image rotated so North is up, same with the Celestia grid.
By the way those streaks sure look like artifacts to me!
Click to view attachment

I think that grid needs rotating clockwise quite a bit.

HA! (I knew you would catch me!). Been looking at that too. I'm not sure the raw image itself it righted with north up correctly. Lets see what a little tweaking can do.

Here is a preview image with a grid:

Wow, awesome VP!

That's very nice. Any chance that could be done on 'looking ahead'?
AND
Can you tell us whether that 9 hour cloud imaging campaign on 15th Feb. actually took place? There's still only the one set of 4 images on the public website.

The problem might be as simple as the cloud layer obscuring the lat/lon grid. Try pressing 'i' to disable clouds.

I've considered modifying Celestia's code a little so that the grid is displayed over the cloud layer. I'm not absolutely convinced that this is a good idea, as it could produce odd looking results for planets with a thin cloud layer (e.g. Mars.) Let me know what you think...

--Chris

Probably not. We are trying to make these look a bit cleaner, a bit more realistic if you will (though obviously, that isn't quite the case with Titan already). Rest assured though that I try to rotate so that north is up in any graphics I use in "Looking Ahead"

And let's... not talk about that imaging campaign... we at least got those 4 images. And those 4 are quite good. But still. Titan hates me. It knows I cheated on it.

Oh..wow! That did the trick! And the surface features are revealed as well! Whoo-hoo!

You are a genius CC! Pressing the i got rid of the clouds on Titan and there is the superimposed grid and surface. Now to get things aligned better.

Here's a coordinated view between the Cassini Raw (contrast modified) and Celestia:
Click to view attachment

And here is a zoom using Photoshop (magnetic lasso is your friend) to select and detail some of the lat/lon grid:
Click to view attachment

The cloud streak runs from WNW to ESE. From roughly [-45S, 315W] to [-53, 285W]

IIRC, the alignment of this cloud to Mezzoramia is about the same as the alignment of the N Polar cloud to Kraken Mare.
Hmmmmm.....

-Mike

Here is another crop of a contrast-enhanced image, this time overlaid by VP's lat/lon grid (VP's posted image/grid rotated ca. 25 degrees clockwise):
Click to view attachment
(Elba Facula is centered near [-10S, 0])
-Mike

Kraken Mare again:
http://saturn.jpl.nasa.gov/photos/raw/rawi...?imageID=185908

Well I know this is a bit late but I had to make ammends. Nice work by VP and Mike on previous page! The Celestia Titan grid-surface map is nice however when it comes to locating clouds there is likely to be an error as they are considerably above surface level!

Hmmm. Note to editor: I cannot seem to upload my photoshop files anymore. Anyone else having trouble?

Well that time things worked!

Click to view attachment

Another beautiful shot of the northern 'dark surface region' emerging from night (appropriately released on our own spring equinox).

http://saturn.jpl.nasa.gov/multimedia/imag...8/N00132269.jpg

Here's a bit of a stretch on that one...

Phil

Click to view attachment

Thanks for that, Phil. The toe of Italy seems to be falling off. Maybe it was never that well attached? The discovery image of Kraken Mare is annotated with a rather inclusive shoreline despite some bright pixels inside the boundary.

http://upload.wikimedia.org/wikipedia/comm...Kraken_mare.jpg

Nice work on this latest Titan image!
Kraken over the last several years appears not to have changed radically. (see images below). I wonder if it has been substantially maintained by the persisting ethane/methane rain clouds of the north pole region (PIA09171), from runoff via inflowing streams visualized in previous SAR’s (PIA09217) as well as from underground sources via sapping from methanofers. Its persistence may suggest its relatively deep if indeed it’s liquid.

Click to view attachment

Nice one 'rivers. I was hoping someone would pull the Kraken images together to facilitate comparisons. There have been others that you don't show there, including a couple from the last few months. I think it would be a worthwhile project (beyond my skills) to assemble them all.

There are certainly quite obvious superficial differences between the 07 images and the 09 one in your collage, including some in the foot of Italy region. I don't attribute much significance to that yet because there are so many factors other than real surface changes that could affect the tone values in the images.

Southern cloud again - is it in the same place? (EDIT: 40S?)
http://saturn.jpl.nasa.gov/multimedia/imag...8/N00132562.jpg

Quick estimate below: appears to be between -45 and -60 S

Click to view attachment

Here is animation of the Titan cloud image mapping to the Celestia grid. In addition to the cloud Hotei arcus stands out, the latter appearing as a fan-shape bright object at the bottom center of the image.

Click to view attachment

Here’s another raw image (N00129016, taken 2-4-09) which displays Hotei arcus nicely!
Click to view attachment

This a raw image from the Dec 21, 2008 T-49 flyby. The image is an inbound shot from 149,000 km of the Hotei region. ? is this a little cloud streak?

Extremely little.

HA HA lets try that again!
N00126798.jpg was taken on December 21, 2008 and received on Earth December 22, 2008. The camera was pointing toward TITAN at approximately 145,059 kilometers away, and the image was taken using the CL1 and CB3 filters. It appears to show a little cloud train ... but is it or not!

Click to view attachment

The current 16 day orbits provide good mid-rev non-targeted flybys that are useful for much more that cloud hunting. Here's Menrva:

http://saturn.jpl.nasa.gov/multimedia/imag...9/N00133457.jpg

EDIT: For some reason that one doesn't expand to the full res version. This one does:

http://saturn.jpl.nasa.gov/multimedia/imag...9/N00133456.jpg

And here is the approximate location of above raw image (slightly enhanced) on the Celestia Titan grid.
Click to view attachment

That's because the other one was a SUM2 image, 512x512 pixels in size.

A belated thanks for that explanation.

Clouds again:

http://saturn.jpl.nasa.gov/multimedia/imag...9/N00135075.jpg

a bit of contrast fiddling with that last image.

Phil

Click to view attachment

I used the MT1 filtered image to subtract away from the combined N00135078 and N00135079 images.
(This idea is based on Jason's abstract; he ratio'd away the MT3 image to correct for the atmospheric lighting effects)

Then I stretched the heck out of the resulting image:
Click to view attachment

The lowest band (also seen faintly in Phil's image) is at about 40 N.
(Menrva is the lighter gray spot.) I really have no clue what I am talking about.

-Mike

[EDIT: This is the N Polar region]

Another uber-stretch with a different set of images N00135074-76, MT1 is N00135077.
Click to view attachment

The lowest arc is still present (and better seen in this set)
Click to view attachment

Nice work Mike and Phil. Working with Phil's image one can project them on a Celestia grid as below. Most clouds project between 60 and 45 deg latitude.

Click to view attachment

Electric Cloud-O-Vision image of N0013574-76 [MT1 = -77]:
Click to view attachment

(Pseudocolorized areas where polar clouds are brighter than background. Pseudocolor scales to relative cloud brightness; purple=darker clouds/haze, red = brightest cloud/haze)

[EDIT: Image details can be found here: http://www.flickr.com/photos/31678681@N07/3487876831/]

I flipped my image in the earlier post to put north at the top. Thanks for the tip, Mike.

Phil

It's interesting to see just how localised the very brightest colours are there. Would a single active convection cell look like that? I hope we get some follow-up images.

I'm not sure. The overall brightness in that region might be an artifact of the subtraction process between the ISS (CL1/CB3) and the MT1 image.

The overall brightness should be a function of cloud reflection+haze reflection+funky specular components from haze+cloud+atmosphere+surface w/respect to MT1 brightness.

To really see how big the bright cloud part is, it would be necessary to normalize out the bright cloud with respect to the bright haze and bright (specular?) atmosphere.

That should be doable....later....