[Moderator's note: This thread contains images from the Iapetus 2007-09-10 flyby and discussion of them. It was created by splitting this thread which contains pre-flyby discussion]


Another CL-UV3-GRN-IR1 set was posted today, though Iapetus seems to have been hiding from the green and IR filters...here's my best effort at making something from the CL and UV3 images. Lots of topography on the limb!

--Emily

TED!!!!!! Should I or shouldn't I??

I actually like the color in this one best. The stretched color views tend to oversaturate Cassini Regio.

Here's a quick collage of some of the lowest and some of the highest resolution color imagery we got of Iapetus in the past 3 years:


To think that in less than 4 days we'll have images with resolutions up to 1000 times better than the best shown here is exciting to say the least.

ISS_049IA_IAPETUS002_CIRS is now on the ground:

Clear Filter Frame: http://saturn.jpl.nasa.gov/multimedia/imag...iImageID=125907

This was supposed to include a true color filter set (BL1, GRN, and RED), but it looks like the shutter times were a tad off and the RED and IR2 images were taken after CIRS pointed away from Iapetus (it points away from its target at the start and end of observations for calibration purposes). However, there is a UV3-GRN-IR1 filter set available from some industrious individual. The auto stretch feature appears to be working now so you guys should be able to do something with this data set.

Some interesting topography is visible in the crescent seen here, including the impact basin in south-central Cassini Regio, a pair of ridges to the northwest of the impact basin in north-central Cassini Regio (these things need names!!), and the equatorial ridge.

You know what, that's it, I am instituting a system of nicknames for the impact basins on Iapetus. These are just nicknames. In keeping with the official naming scheme for Iapetus, characters and places from the Song of Roland, all the nicknames will be predominately French. Map upcoming.

Here's an IR3/GRN/BLU combination image from 7 september:

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Here is a map of official names (in green) and nicknames (in red):

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Frosty, Sam, Yukon, Cornellis - doesn't sound french at all...
Anxious about calling the whole crater triplet Snowman - or say better in french:
bonhomme de neige...

I think IAU will get in trouble creating names from 'The Song of Roland', simply because of a limited number of characters there!

Nomenclatura in french seems to be one solution.
I personally would prefer naming surface structures after their appearance, like the Snowman for instance.

Bye.

Nice to have CAP-Team's image and VP's names for reference. I think I can see Lionel on the terminator of the 9/7 image and maybe Jeanne near the limb. The NNE edge of Henri may be a spot where the bellyband diminishes eastward (into a flat area) and we thus would be seeing a shadowed slope along the bellyband in the image. If we can make out as far as the SW edge of Henri that could fill in a blank sliver on the map.

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I'll go ahead and opine that we might eventually want a "Claudette" just to the east of "Claude"

this is a simulated view, using VP's map with nicknames in Xplanet:

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May I propose refering to the large elongated crater S of Joan on the edge of Casini Regio as Papillion ??

thanx for the consideration

It's Frosty, Sam, and Yukon Cornelius, btw... All the names have a French theme, except those. They are named after famous (in the US) snowmen. Frosty is obviously from Frosty the Snowman, and Sam and Yukon Cornelius are from the annual TV holiday special, Rudolph, the Red-Nosed Reindeer.

ugordan Your image is amazing! I appreciate the effort to make that montage.

Great News! New pics!
WOW! http://saturn1.jpl.nasa.gov/multimedia/ima...3/N00091644.jpg


My sad attempt at stacking.

Great stuff! Sadly the sole long-wavelength image seems to have missed, so I had to fudge for the red channel. The version below consists of clear for red, a stack of four green images for the green (clear plus 3 polarizers), and, for blue, the UV3 channel with cosmic ray hits erased or corrected for by copying bits from the polarized channels where cosmic rays hit the sunlit part of Iapetus. Then I converted to Lab, replaced the lightness with the clear image, and went back to RGB.
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That's some pretty rumply looking topography in the southern hemisphere basin! The "belly band" seems to look sorta segmented, with little north-south notches cut into it.

--Emily

The South-central Cassini Regio impact basin ("Henri") appears to have a central massif, which matches with the morphology of similar basins in north-central Cassini Regio ("Aimee") and northeastern Cassini Regio ("Joan").

Not sure what is up with the equatorial ridge.

I tried stacking 6 of the most recent images in RegiStax. They were obtained at a range of ~490,000 km. I omitted the polarized UV images as they looked too noisy and fuzzy.

This version has been sharpened with wavelet processing followed by postprocessing in Photoshop (mainly brightening it slightly). Probably overprocessed, doesn't look as nice as Deception's version above:

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The following version has been processed to reveal the nightside. As these are not long-exposure images and the JPG compression destroys dark, low contrast details not even large scale features are visible on the nightside. However, Iapetus' entire limb is apparent and the irregular terminator looks nice:

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It sure looks like the Belly Band postdates Henri and is superimposed on top of it, which has some interesting implications. I guess we'll be able to tell for sure in the next set of images.

If the degraded basin that is right next to Henri is going to be visible on this flyby, maybe it should get a name too.

Which degraded basin? Henri is rather degraded.

Michael Capobianco, that's my sense too, that the equatorial ridge here is built-up on top of Henri's ejecta.

Hey, how's this for a "family portrait"..? Pioneer 11 and Voyager 1 - with New Horizons - all in the same field of view as Iapetus during tomorrow's encounter?

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I know we won't actually see them, but kinda cool to think they'll be "in the area"...

Just a little update. This evening, we can expect to get three observations down from the spacecraft: ISS_049SA_SATSYSFIA001_PRIME, ISS_049IA_M33HRS001_PRIME, and ISS_049IA_GLOBMAPG001_PRIME . The first two is meant as a family portrait image set. SATSYSFIA001 can be thought of as a Kodak moment-type observation as Cassini images the entire Saturnian system from near-Iapetus using both the WAC and NAC cameras. Expect lots of ring NAC images and distant images of all the major moons of Saturn, plus a Wide-angle camera overview. M33HRS001 is an Iapetus observation immediately following SATSYSFIA001. Iapetus will almost fill the view in this observation. Hopefully, the targeting will be spot-on and I can use this image for controlling the other crescent/Saturn-shine images that come down later tonight and tomorrow. This view will have a pixel scale of 1.7 km/pixel. Finally, ISS_049IA_GLOBMAPG001_PRIME will also come down. This observation is a two-frame mosaic of the crescent at 1.3 km/pixel. CLR and UV3/GRN/IR1, as well as GRN polarized, images are expected for each footprint. These images are expected between 9 and 10pm tonight (though they could show up as early as 8:30pm, depending on how the Raw images page ingests images).

Tomorrow morning images from the ISS_049IA_LIMBTOPOG001_PRIME and ISS_049IA_SATUSHINE001_PRIME observations will come down. LIMBTOPOG001 is a two-frame mosaic of the crescent at 800 m/pixel. CLR and UV3/GRN/IR1, as well as GRN polarized, images are expected for each footprint. Saturn-shine observations over both poles are also expected with this observation. Expect anywhere from 0.82 to 1 pixel of smear in these Saturn-shine images. ISS_049IA_SATUSHINE001_PRIME is also expected. This sequence includes a four frame mosaic over the the crescent, 2 three-frame mosaics in saturn-shine over the polar regions, a frame over the ridge, and a frame over the south-western part of the impact basin in northeastern Cassini Region ("Joan"). These images are expected to be on the raw images page sometime between 7:15 and 8:15 am tomorrow morning.

Emily, those features along the ridge are superimposed impact craters:

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also made with infrared, GRN and ultraviolet

Ah. Of course. It's obvious, now that you've explained it to me. I didn't recognize them because of the foreshortening. If it were less of a crescent view, there would have been craters along the ridge to compare them to, like in the image you showed; but with just the crescent illuminated it was quite mysterious.

Nice map!

--Emily

Here we go again!

http://saturn1.jpl.nasa.gov/multimedia/ima...iImageID=126174

There's another one just to the southeast of Henri that is about the same size but is even harder to see. There isn't much left of it, but you can see it when it is close to the terminator.

Somebody pointed it out a year or two ago -- I can't remember who noticed it first.

[Edit: If you look at the collage of Iapetus images from the first page of this thread, it's visible in the images from the 7 o'clock and 8 o'clock positions on the "wheel".]

I hope we get the chance to see the Iapetus shots within the next couple of days after the close encounter. Good job this is happening on a Monday morning -- it would've been torture if it had been on a Friday.

The latest set looks like ISS_049IA_M33HRS001_PRIME and appears to be perfectly targeted. Well done team!

EDIT: and here's my composite of that one. It's got stacked IR and Red for red, stacked green and clear for green, and just blue for blue (the UV3 one was a bit JPEGGy and cosmic-ray-hit to do much with)
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I was busily erasing cosmic ray hits from the short-wavelength channels when I noticed that there seemed to be a "hit" in the same place on two of the channels. Three light spots, actually, repeated from channel to channel, which means they weren't hits, they were features; they were the pole-facing southern rims of three craters north of the equator. Neat! There was also one longer-exposure clear image in this observation, and you can see the outline of the limb -- with a hint of some interesting topography -- and maybe one mid-sized crater in the north polar area by Saturnshine, but not much else.

Also a few images from ISS_049IA_GLOBMAPG001_PRIME seem to be up, but not all of them.

Bedtime for me; I'll have to wait until tomorrow to see what Santa has brought!

--Emily

[...]

This one is about 60,000 km closer, crudely enhanced and rotated for easier interpretation. Looks like a crater chain running parallel to the ridge.

Man must explore. And this is exploration at its greatest - Dave Scott

I just can't get over the strangeness of that mountain chain so abruptly interrupting the otherwise smooth curve of Iapetus' horizon. It is unnatural -- and yet wonderful, too.

And yes, there does seem to be a linear feature running parallel to the equator. Maybe more than one. That makes the phenomenon all the stranger.

I was struck by how lumpy this body is as seen in this overexposed image. Another thing is the 3 stars visible aren't streaks at all despite longer exposure. Cassini was obviously tracking Iapetus and the stillness of the stars suggests Iapetus wasn't moving in Cassini's windshield much at the time - more or less just growing bigger and bigger.

Thought I'd have a go, everyone else is going to!

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Wow!!! http://saturn.jpl.nasa.gov/multimedia/imag...iImageID=126214
This is it, at 62 000 km it's already twice the resolution we ever got!

Just look at that rigde, like some alien spine creeping around the moon!

Where's that swear bucket when you need it?

Amazing views and it's only going to get better.

I don't actually remember, how high are the peaks in the mountain ridge?

The highest ones are about 20 km high.

Not unexpectedly, that ridge looks ancient. At a quick glance it seems just as heavily cratered as the terrain near the ridge.

I noticed several 'black' images. I hope these are Saturnshine shots that the automatic contrast stretch didn't handle well and not images where Iapetus got missed. The fact that they are all CL1/CL2 suggests the former may be the case.

Looks like saturnshine pics:


Much noise in there...

Till later...

Am I seeing things that aren't actually there, or is there a parallel feature running alongside the main ridge on both sides..?

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I believe the 10 consecutive "black" images are part of ISS_049IA_SATUSHINE001_PRIME:


I suspect they're black because cosmic noise confused the histogram stretcher. Saturn is in a more favorable saturnshine phase now, ~35° (rev B/C was ~70°).

Funny how we're seeing WAC frames now similar in resolution to what NAC saw a couple of days ago:

Except WAC PSF makes everything look blurrier.

Here's the view with saturnshine on the limb. A composite of three frames.

Phil

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Phil, I don't know why, but that composite reminds me of Voyager 2 Triton encounter for some reason.

Probably 'cause Iapetus' black streaking resembles the wind-blown geyser plumes.

Also: Stu, that's an interesting observation about the attendant linear features paralleling the main bellyband. The one on the right looks like it might be just a fortuitous arrangement of craters -- but it does seem that there might be something there.

Today's the day and I'm absolutely a-bubble with excitement. Dreamt last night that the dark material on Iapetus was billions and billions of 2x3x5 (or 4x9x25) meter-tall black monoliths...

And Oppy is getting ready for the entry into Victoria. Can life get much better?

--Bill

Well, I guess you guys get the real-time feed... interesting.

Stu, the ridges parallel to the main ridge were seen during the New Year's 2005 encounter. According to Giese et al. (in press in Icarus), these are caused by flexure as the heavy load of the ridge is supported by the thick lithosphere.

What do you mean by this?

P.S. Bill, it can always be even better!

Usually, we get the images several hours after the end of the downlink. That's how I calculated the 7:15-8:15am PDT arrival times for the images on the JPL raw images page. During the Iapetus encounter, however, we get the images in a "real-time" feed, meaning we see the images shortly after (within 15-30 minutes) they hit the ground, during the downlink. However, I expected the JPL raw images page to load the images several hours after the downlink, on the "Non-real-time" feed. But the fact that people were already looking at the images at 4:20am PDT tells me that you guys are getting them as soon as we are seeing them.

Well, we're past C/A now. Hope we get some images soon!

BTW, I assume that the scale of the "bellyband flexure" probably tells us something about the rigidity of the Iapetan lithosphere (and perhaps its thickness, at least thickness-at-the-time)?

@VP: Well, if it's any consolation to you, the last downlink (yesterday, starting 14:15 UTC) certainly didn't feal "real time" to us. Unless the imaging data was downlinked at the very end of the pass, there was an obvious delay because no new images were posted on the raw page as of 21:30 UTC. I'm inclined to think the raw posting mechanism isn't totally automated, rather it is triggered by someone after the DL is complete. Who knows...

Rob, the way I see in Emily's table, we might not see any new images until tomorrow's huge 14 hour, partly redundant downlink. The next downlink (2 hrs duration) might only contain RADAR SAR data. That huge downlink is scheduled to begin something like 07:00 UTC September 11th.

I know there are a couple downloads scheduled during the flyby. Anyone know approximately how often and when the Raw Images site is going to updated today?

And may I add along with everyone else, Oh my f***ing g**d!!!


(no, no, that was "feeling good". You people think I would really swear like that on a public forum?)

Oops. Sorry. I didn't refresh my browser for a few minutes, and the "how often are we getting downloads" discussion has already happened.

But I'm still feeling good. This is great stuff. Flyby of a lifetime.