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ngc3314
2004-Oct-24, 07:45 PM
I don't see a heads-up yet on this - the Cassini raw image page is showing nice Titan images by now (midday Sunday, GMT -5). Playing around with contrast and filtering on one of the filters that peeks through the haze, it looks more like Mars than anything else I've seen. Maybe this time there's a nonzero chance that some of those markings are contemporary shorelines...

Chip
2004-Oct-24, 10:18 PM
Do you mean some of these images? From the NASA "raw images" link on the Cassini website. (The photos not the paintings.) :wink:
http://saturn.jpl.nasa.gov/multimedia/images/titan/index.cfm

Which ones looks Mars-like?

dummy
2004-Oct-24, 10:44 PM
I'd bet on it being these (http://saturn.jpl.nasa.gov/multimedia/images/raw/raw-images-list.cfm?browseLatest=1). There are some really cool looking pictures coming in.

ngc3314
2004-Oct-24, 10:59 PM
I'd bet on it being these (http://saturn.jpl.nasa.gov/multimedia/images/raw/raw-images-list.cfm?browseLatest=1). There are some really cool looking pictures coming in.

Sorry about that (I had already wiped out the window...)
One example of that sort of detail is in http://saturn.jpl.nasa.gov/multimedia/images/raw/raw-images-details.cfm?feiImageID=25453

BigJim
2004-Oct-24, 11:30 PM
I've been looking at the same images. If you increase the contrast a little, you can see a lot of interesting detail. I think that these images are centered on the "bright continent". I don't see any obvious impact craters, except maybe the object on the far left of the above image.

ToSeek
2004-Oct-26, 05:28 PM
Eyes on Xanadu (http://www.spaceflightnow.com/cassini/041025xanadu.html)

Doodler
2004-Oct-26, 05:44 PM
How soon can we expect a verdict on whether we're looking at liquid surface features? (I'm assuming a few days to a week, unless something I'm not trained to see hit the "Eureka" button.)

Reverend J
2004-Oct-26, 08:06 PM
Hmmm...

I was looking at:

http://saturn.jpl.nasa.gov/multimedia/images/raw/casJPGFullS05/N00023203.jpg

Is it me or does it look like on the middle right hand side there seems to look like a crater that has been filled in by something either liquid or a very dark materal?

Upon futher checking it looks like the spot moves around a bit, sad. Oh well, had my hopes up for a sec. :)


Rev. J

[Edited after checking 20 more pics]

Bozola
2004-Oct-26, 08:11 PM
Hmmm...

I was looking at:

http://saturn.jpl.nasa.gov/multimedia/images/raw/casJPGFullS05/N00023203.jpg

Is it me or does it look like on the middle right hand side there seems to look like a crater that has been filled in by something either liquid or a very dark materal?

I'd check several pictures and the 'O' seems to be in the same spot, thus not a speck on the camera or anything.

Interesting :)

Rev. J

I fell for that as well. If you look as one of the "cue ball" photos, it's there too. Kucharek pointed out that it's crud in the optics, elsewhere.

kucharek
2004-Oct-26, 08:14 PM
Compare e.g. with http://saturn.jpl.nasa.gov/multimedia/images/raw/casJPGFullS05/N00022711.jpg

Bozola
2004-Oct-26, 08:23 PM
Well...you know...it could be an alien doughnut that's pacing the probe...

Andromeda321
2004-Oct-26, 08:27 PM
Interesting little ring feature... how big is it do you figure?

Nowhere Man
2004-Oct-26, 08:31 PM
Interesting little ring feature... how big is it do you figure?
Half a millimeter, I reckon.

Fred

Reverend J
2004-Oct-26, 08:39 PM
Interesting little ring feature... how big is it do you figure?
Half a millimeter, I reckon.

Fred

I laughed pretty good when I read that. :lol: Like I said in the edit above, once I looked at about 20 pics I noticed it did move around (not to much though) Oh well, I guess I'll stick to being a chemist :)

Evan
2004-Oct-26, 08:54 PM
I would guess that it is an artifact added later in the image processing, odd as that sounds. I took that section of the image, pixel resized it (no upsampling) and did a histogram equalize. You can clearly see the jpeg artifacts in the transmitted image data but not in the ring. Interesting.

http://vts.bc.ca/pics/ring1.jpg

Or, I could be wrong :D

From FAQ at NASA:


What are those dark donut shapes?

Small donut-like dark spots in images are actually out of focus dust specks on the filter wheels, lenses or other parts of the optics of the cameras. Because there is no way to clean the cameras in space, more of these spots may appear as the Cassini mission progresses.

MoonToMars
2004-Oct-26, 08:55 PM
What do you people suspect the pictures and the environment will be like when the li'l robot lands on Titan?

I am suspecting large sheets of ice, similar to Europa. My only fear is that the machine will be doing nothing but sending bubbles under water. #-o

It's certainly too cold for life on the surface, so I don't expect aliens to be waving into the camera.

MoonToMars
2004-Oct-26, 09:08 PM
Yeah, jpeg artifact all over this image.

Of course, me being the nutcase that I am I did see this ring before on Saturn if I remember right. I was thinking it was something on the camera, otherwise It'd have to be a storm of some sort right?

http://img28.exs.cx/img28/1826/Jpeg_Artifact.jpg

There's my zoom..

MoonToMars
2004-Oct-26, 09:10 PM
Ehh yeah nevermind. I think it's just something on the photographs. Because this image of Saturn
http://saturn.jpl.nasa.gov/multimedia/images/raw/casJPGFullS05/N00022979.jpg Contains the same ring. I think they all do... #-o

M_Welander
2004-Oct-26, 09:55 PM
You can clearly see the jpeg artifacts in the transmitted image data but not in the ring. Interesting.
Visible JPEG artifacts only appear in macroblocks that have too much high frequency data for being encoded using the selected compression rate. As the ring is large enough to cover several (roughly 9-12) macroblocks, it follows that each macroblock will only have to cover a small part of the ring. Since the ring basically is just a light shade going darker and then brighter again as you move out, every macroblock will practically just be a single gradient. That means it compresses very well. The surface around the ring, however, is quite noisy, and thus compresses less well. That is the reason why the surface has visible JPEG artifacts while the ring has not.

The Bad Astronomer
2004-Oct-26, 10:00 PM
Donuts are caused by specks of dust inside the camera. Usually there is a transparent window (well, in this case, transparent in IR) in front of the detector. A piece of dust gets on it, and is WAY out of focus. It forms a dark donut like that.

Donuts are impossible to remove with image processing, though it's possible to diminish them somewhat using a process called flat-fielding (I'll let the curious google that for more info). But I've seen thousands of 'em, and this is yet another one.

Matt McIrvin
2004-Oct-27, 12:27 AM
The big dark marks that look like seas have been seen from Earth, and there was some speculation that they were liquid hydrocarbon seas. But my impression was that the VIMS spectrometer images Cassini took on the first, much more distant Titan encounter instead indicated that those regions are mostly water ice, and it's the light areas in these infrared pictures that have more organics. So big liquid seas are unlikely, I'm afraid.

Maksutov
2004-Oct-27, 03:27 AM
Just got an email from Carolyn Porco in which she mentioned that the latest images are now posted at http://ciclops.lpl.arizona.edu/. At that site the images are available in a variety of formats and resolutions.

Amazing stuff!

Wolverine
2004-Oct-27, 03:37 AM
Amazing stuff!

Very cool! Thanks for the url. 8)

Wolverine
2004-Oct-27, 04:15 AM
They've now posted some of the first shots on the main Cassini page, including this one (http://saturn.jpl.nasa.gov/cgi-bin/gs2.cgi?path=../multimedia/images/titan/images/pia-titan-1-2.jpg&type=image). I fully expect to see a new Hoagland page detailing the sacred geometry of donuts up my morning.

EFossa
2004-Oct-27, 05:06 AM
.........I think Titan is completely dry :o

Maksutov
2004-Oct-27, 07:04 AM
Yeah, jpeg artifact all over this image.

Of course, me being the nutcase that I am I did see this ring before on Saturn if I remember right. I was thinking it was something on the camera, otherwise It'd have to be a storm of some sort right?

http://img28.exs.cx/img28/1826/Jpeg_Artifact.jpg

There's my zoom..

Using my custom AI image analysis software, it was easy to determine what this "donut" actually is. Just click on the icon below:

http://img39.exs.cx/img39/3659/Titanic2.th.jpg (http://img39.exs.cx/my.php?loc=img39&image=Titanic2.jpg)

The analysis was pretty difficult to do, especially trying to get the subject to stand still.

Kullat Nunu
2004-Oct-27, 01:10 PM
http://saturn1.jpl.nasa.gov/multimedia/images/raw/casJPGBrowseS05/W00002395.jpg

Another kind of ring: Sun behind Titan :o

Deer Run Observatory
2004-Oct-27, 01:52 PM
These images are looking great. What's really great is the fact that this is just the first of a series of passes that get closer and closer each pass should show more and more detail.

If I'm not mistaken the Huygens probe has an external microphone on it so we will be able to for the first time hear sound on the surface of another solar system object (moon doesn't count, no atmosphere = no sound and mics in spacesuits don't count ) :lol:

Here's my list of odds of the sound we'll hear as the probe decends through the atmosphere to the surface:

10^1000 to one Tap Tap "Is this thing on?"
50% Splash as it lands in liquid
50% Thud as it lands on solid surface
25% It survies on the surface long enough to record some erriely cool wind sounds.

Anonymous
2004-Oct-27, 02:13 PM
Personally, Iím growing very impatient awaiting the radar data. That should settle the whole liquid-solid surface features question, yah?

aurora
2004-Oct-27, 03:22 PM
.........I think Titan is completely dry :o

The rightmost image on this page

Revealing Titan's Surface (http://saturn.jpl.nasa.gov/cgi-bin/gs2.cgi?path=../multimedia/images/titan/images/PIA06125.jpg&type=image)

if you load the higher res image, there is clearly an impact crater in the dark area, indicating to me that at least some (if not all) of the dark area is solid, and not liquid.

Having said that, I think the general lack of lots of craters indicates (like it does for Europa) or circular impact basins means that there is some kind of resurfacing activity that has occurred.

Evan
2004-Oct-27, 03:45 PM
Well, maybe. It could also be the ring wall of a flooded crater.

Jerry
2004-Nov-01, 05:42 PM
Donuts are caused by specks of dust inside the camera. Usually there is a transparent window (well, in this case, transparent in IR) in front of the detector. A piece of dust gets on it, and is WAY out of focus. It forms a dark donut like that.

Dust or crumb?
Somebody might have been eating a donut while they assembled the lens.

Leper
2004-Nov-03, 04:49 AM
Hard to have impacts craters with a atmosphere that thick.

tlbs101
2004-Nov-04, 04:52 PM
Donuts are caused by specks of dust inside the camera. Usually there is a transparent window (well, in this case, transparent in IR) in front of the detector. A piece of dust gets on it, and is WAY out of focus. It forms a dark donut like that.

Dust or crumb?
Somebody might have been eating a donut while they assembled the lens.

Cassini's final assembly (including the attachment of Huygens) was done in a very large clean room. We have pictures here at work, of the large room with Cassini being assembled. The technicians were all wearing their "bunny" suits. IIRC it was a class-1000 clean room. I had wondered for years if that was "clean" enough. I finally have an answer to that in some form, anyway.

Doodler
2004-Nov-04, 06:15 PM
Donuts are caused by specks of dust inside the camera. Usually there is a transparent window (well, in this case, transparent in IR) in front of the detector. A piece of dust gets on it, and is WAY out of focus. It forms a dark donut like that.

Dust or crumb?
Somebody might have been eating a donut while they assembled the lens.

Cassini's final assembly (including the attachment of Huygens) was done in a very large clean room. We have pictures here at work, of the large room with Cassini being assembled. The technicians were all wearing their "bunny" suits. IIRC it was a class-1000 clean room. I had wondered for years if that was "clean" enough. I finally have an answer to that in some form, anyway.

Having designed a Class-10000 Clean room in my time with an architectural firm, I can tell you the airflow gymnastics necessary to pull it off are insanely difficult and expensive. Building a Class 10k necessary to house a deepspace probe the size of a bus may not be feasible.

I'd love to see the construction docs on the class 100,000 clean room they build for the Genesis samples.

Grizzly
2004-Nov-04, 06:34 PM
Has anyone considered that the dust or contamination on the lens might have occurred after liftoff?

Wasn't there some problem with contamination on Deep Space 1 or was it NEAR? Blow-by from the propellant was the cause then.

You also have to consider that the probe has been travelling now for a number of years, even if the camera is secured for most of the journey couldn't some contamination have occurred in transit, perhaps in the Jupiter fly-by? Venus? Do we have examples of pictures from then that would indicate that the problem was present?

----
Videre est credere
Seeing is believing

tlbs101
2004-Nov-04, 10:49 PM
Doodler is correct in that it is very expensive to build clean rooms, although we have built temporary class-100K rooms here at work, when they are needed without too much difficulty. The AC/filter units are usually the same size as the amount of working area they clean!

I am probably not recalling correctly that it was a class-1000, but I seem to remember that Cassini's assembly room was, at the time, the largest clean room (of whatever class it was) in the world.

There is a definite possiblity that the optics became contaminated during the journey to Saturn, also.