VP: thanks for the info on the parallel ridges, there was a bell ringing at the back of my mind about that but I'd forgotten the details.

Seriously guys, how amazing is this? Front row seats for almost real-time exploration of one of the solar system's most fascinating bodies?! I've managed to see Iapetus in my humble 4.5" telescope a few times... on very clear, still nights, through the light pollution above Kendal... and now I'm looking at images of a dinosaur spine crater-pocked mountain ridge on its surface, almost as soon as they reach Earth! What a fantastic example of what Doug was talking about in his recent presentation - the sheer joy and genuine excitement of "joining in" with a mission and feeling part of it. Many, many thanks to whoever (deliberately or accidentally!) is allowing us to drool over these pictures so quickly.

A true "THIS is how it should be done!" lesson to other space agencies, mentioning no names of course, haha...

[...]

Hi

Impressive flyby now And some images to produce .

These are my tries :
Narrow angle camera, today.
Click to view attachment

RVB wide angle cam
Click to view attachment
And an oversaturate pic to view more clearly color differences
Click to view attachment

I'm waiting for narrow RVB images...

Here is what I could glean from the playback schedule. Please take time values with a grain of salt. They can be off by a few hours (usually on the plus side). So if ORSHIRES001 doesn't show up at 1:06am PDT, don't come here screaming that something has gone wrong. BTW, all times are in Pacific Daylight Time (this is just copied from my personal notes):

FP1NITMAP001_CIRS - Monday, September 10 - between 2:43 and 3:49 pm
CASSREG001_PRIME - Tuesday, September 11 - between 12:13 and 12:16 am
ICYMAP003_UVIS - Tuesday, September 11 - between 12:16 and 12:31 am
ICYEXO009_UVIS - Tuesday, September 11 - between 12:31 and 12:45 am
ORSHIRES001_VIMS - Tuesday, September 11 - between 12:49 and 1:06 am
FP1DAYMAP001_CIRS - Tuesday, September 11 - between 7:19 and 8:00 am
IAPETUS013_VIMS - Tuesday, September 11 - between 12:51 and 1:00 pm
REGMAPTRL001_PRIME - Tuesday, September 11 - between 2:59 and 4:07 am
REGCOLTRL001_PRIME - Tuesday, September 11 - between 4:22 and 4:42 am
IAPETUS010_VIMS - Wednesday, September 12 - between 8:05 and 9:05 pm
LIMBTOPOI001_PRIME - Wednesday, September 12 - between 8:05 and 9:05 pm
IAPETUS004_CIRS - Thursday, September 13 - between 7:50 and 8:50 pm

Thanks indeed to all those who have made this possible!!!!

Any one else out there old enough to remember the JPL "Blue Room" broadcasts during the Voyager mission? Our local PBS station aired those, and I will never forget watching the commentary of Hal Masursky and, I believe it was Larry Soderblom, as the first Voyager close encounter Io images were being downlinked. The sheer JOY of major discovery happening before our eyes!!!!!

Now here we are 28 years later watching Iapetus reveal itself to us all with data we can save and play with.
Another world develping before our eyes... are there really words that can express the emotions here????

Yes, indeed Stu.... this is how it should be done.

Craig

Of course, Saturnshine imagery will always only show one hemisphere, the sub-Saturnian hemisphere, regardless of where Cassini is, because that's the only hemisphere that'll get sunlight from Saturn. I think you know this, it just wasn't clear from your post, and in fact I always forget this fact -- you'll never get any Saturnshine images of the anti-Saturnian hemisphere, because that hemisphere never sees Saturn! The point you're making about getting a daylit view primarily of the anti-Saturnian hemisphere is a good one and one I keep forgetting to make.

When I was talking with Tilmann at the satellites conference about this, he expressed concerns about the quality of the Saturnshine images because of this very geometry; that Cassini would not be able to use its vaunted tracking capabilities to keep long-exposure images from getting blurry. If it's flying by, from a distance, excellent tracking can keep the same points on the surface precisely in the same pixels on the detector. But if the moon is simply growing in the field of view as you approach it directly, the points on the surface are spreading out, and there's no way to prevent some of them from moving from one pixel to the next, introducing a spreading sort of blur. So they had to keep exposures short enough that this radial smear would be less than one pixel, meaning for the LIMTOPOG001 observation, the exposure was forced to be shorter than 56 seconds. I notice that on Tilmann's website, the detailed information for each observation includes a "Radial Smear Table" for the saturnshine observations.

Tilmann said something to me about this, which I don't remember perfectly, but it had something to do with avoiding every-other-line-truncation issues with these images by forcing them to occupy a smaller part of the histogram than they otherwise might, so he predicted that many of them would show up on the raw page as black images, annoying people.

--Emily

Here's my stab at the mosaic, click for full-res:


I took care of varying distances between footprints and they match pretty nicely. The dynamic range on this thing is so big I had to overexpose the northern section a bit even while reducing contrast to make Cassini Regio better visible. I'll try a color one next, but the UV frames are smeared pretty badly.

Nice work!

The UV images are really blurry. Just putting them together in an RGB doesn't work very well (first image). However I found that you can get rid of a lot of the blur and still preserve a little bit of the color information by stacking it with the clear-filter image first. Not ideal, but much better looking.
Click to view attachmentClick to view attachment

--Emily

Excellent work on the images sent back so far, well done everyone! Anyone else just want to go to bed right now and wake up when the close-ups are in?

Speaking of which, based on what we've seen today, and the detail we've seen on this part of the Great Wall (HATE "Belly Band", sorry!) has anyone out there an idea just what the images of the Voyager Mountains will actually show? Will we see peaks glinting in the sunlight? More avalanche features? Just curious because I'm giving a talk to an astro society in Carlisle on Thursday night, and although it was meant to be just about Titan I'm making space to feature Iapetus fly-by images too...

Click to view attachment

Even if no-one has any actual predictions, what would you like to see on those images of the mountains?

Here's the best I could do to get some color out of the lower resolution filters. The UV filter proved most problematic (particularly in the right half of the mosaic), with its high noise and blur. I'm not too keen on the blue ice to the north, but its for keeping with the spirit of previous composites.

In the old days, (Mariner 69 was the first instance for me) I remember watching all the US and Canadian news casts hoping they'd cover a flyby. If lucky, they did. Then I went through the newspapers, then rushing to the stores on the following Wednesday to pick up Time and Newsweek. Finally, about 6 weeks later, Sky & Telescope (and briefly Star & Sky - remember that one?) would have the best pictures.

How times have changed! Having them almost live, and then having you guys doing absolute amazing stuff has given me a front seat. Life doesn't get much better. Thanks!

I remember during Voyager's approach to Neptune, I would ride my bike to a local newstand and check every paper for news. If I found anthing substantial, I would buy it (on the days I had any money). I would also make trips by the library to see what was in Science and Science News.

Yes, and Aviation Week as well. I'd hate to admit how much pilfering of library magazine pages adorned my scrapbooks! National Geographic was about a 5 month delay. I did manage to buy some amazing books at the book store at JPL during my one and only visit during my honeymoon in 1980. It was closed to the public, and I pleaded that I had come all the way from Montreal and they actually gave my wife and I a pass and we got a bit of a grand tour.

[...]

I used photocopies, but I used to have boxloads. NG was a delay, but the quality was phenominal. I only had rare access to Aviation Week when I would get to go to a larger college library in another town.

I still have the three giant binders full of Io info from when I would go to the public library in my hometown of Leavenworth, KS and print off page after page of info on Io that I could find on the internet or copy from a book.

Beat me to it, Gordan! Here's my effort. (Details will be posted shortly on the blog.)
Click to view attachment

--Emily

Nice one! Looks like your color is more consistent through the footprints than mine, except for the leftmost part where a touch of green is noticeable.

That leftmost one was tough, because it was both dark and dark -- both dimly lit and dark-colored. I really had to sink the levels down low to make it sort of match.

Blog entry now posted here.

Now I gotta go prepare for a $*(#^ dinner party...why can't my relatives check the space calendars before they try to schedule family events?

--Emily

You can often alleviate this problem a bit if your footprints overlap. After you adjust color for each filter, you flip through overlapping layer portions through each RGB filter in Photoshop and take note if brightness appears to change in the overlapping region. You can match colors better this way as you're looking for difference, something the eye's good at picking out.

My wife has a solution for such schedule conflicts when she's working against a deadline.

OK just to stop me thinking about it what is that poorly registered red/green spot in the sky quite near the equatorial ridge in your middle image? A star? I don't see it on other processed versions.

it's these days, same as the day the huygens lander landed on Titan, you'd want to sit and check every tv station and/or website covering the event, hoping to see the new incoming images the first.

Can's wait to see the new high-resolution images from the bright side of Iapetus. Emily did a really nice job with the image posted above!

Yeah, that's a star. There are a few that show up in the sky in the Iapetus images.

Should include the next transmitted image - Iapetus crescent at low southern latitudes, distance 39013 km, resolution 235 m/pxl:
Click to view attachment

The next dowlink:
That's 14 hours 5 minutes after the last transmission, whose images we already enjoyed.
So maybe earliest in 4 or 5 hours - time to have some sleep...

Here's an attempt at stereo on the ridge. Did I do this right? I'm never really sure if I've assembled stereo images correctly; my eyes always give me topo-from-shading and I have trouble looking past that unless things REALLY leap out. The two images I used were
http://saturn.jpl.nasa.gov/multimedia/imag...iImageID=126188
and
http://saturn.jpl.nasa.gov/multimedia/imag...iImageID=126214
Click to view attachment

--Emily

You may need to rotate them so that they are both pointed north up. However, I am not sure there is enough difference between the geometry of the two images. I am assuming you used the two frames from SATUSHINE001? The sub-s/c longitude changed by 1/2 of a degree between the two. I would wait until the WAC from ORSHIRES001 - trigger number 2901 comes down. That would make a much better stereo pair.

Yes, they're the two from SATUSHINE001; the second of them was described as "ridge stereo" so I assumed that's what they were for. But after more fiddling I'm giving up, as it seems that there just isn't enough difference between them to make the point of view any different between "left" and "right." One's 10% closer to Iapetus than the other but Cassini didn't move around the limb enough to make any difference.

--Emily

WOW!!!!!!!!!!!!!!!!!!!!!!! :

http://saturn.jpl.nasa.gov/multimedia/imag...iImageID=126229
http://saturn.jpl.nasa.gov/multimedia/imag...iImageID=126228

Less than 1500 km from Iapetus! Still trying to figure out what I'm seeing, for some reason my brain/eyes combination wants to see cones where I think I should be seeing craters.

Weird, the links to the images no longer work. Here is one of them that I managed to save before this happened:
Click to view attachment

Direct links to the JPGs apparently work:

http://saturn.jpl.nasa.gov/multimedia/imag...3/N00091840.jpg
http://saturn.jpl.nasa.gov/multimedia/imag...3/N00091841.jpg
http://saturn.jpl.nasa.gov/multimedia/imag...3/N00091842.jpg

(as should be obvious from this string of messages I'm rather excited about this )

Those really are amazing!

where did emily and ugordan get the hires of each filter for that crescent image? the only IR1, GRE and UV files i saw were pretty lo-res.

Just stunning. The words "very old" keep coming to mind.

Whatever is making it black must be something akin to electrostatic molecular coating. Even the finest dust or other particles after all these eons would show some kind of accumulation. All we see are raw untouched ancient crater fields.

Reminds me of the closeups of the similarly battered limb of Dione, where as Dione's surface looked like ice, Iapetus's surface looks like rock.

They probably did what I did, combined each color filter image with the full-res, clear filter image.

N00091839.jpg is also accessible by a direct link.

The limb here is MUCH smoother than in 91840, to the "right" of the bellyband and near the start of the high latitude light terrain.

combined them?… that is probably where any abilty i have to do this stuff drops off. i am only combining the IR, GRE and UV into the R, G, B channels in photoshop.

< place embarrassed emoticon here >

ed, where did that image come from...

Because I cannot now open the mid-sized image for the most recent narrow angle frames (as noted above), and then get to their full-rez raw frames, I opened the raw for

http://saturn.jpl.nasa.gov/multimedia/imag...3/N00091828.jpg

and changed the last digits in the address bar to 39 and hit "enter".

Voila.

I just tried looking for the next WA frame after W00035137 and get "The Page You Requested Is Not Available", so we can work around bugs or whatever in the software but not "cheat" and get files that aren't there yet.

Here's my contribution to the Iapetus party:

Click to view attachment

*Yawn* I'm off to bed then!

Click to view attachment
Only six new images have been transmitted so far - probably prior to a large RADAR data downlink.
I think these images are connected with those CIRS observation mentioned above - but actually I'm not sure and I can't appreciate the numbers of NACs and WACs we see there now...

EDIT: Info from Tilmann - 2 are the only ISS-shots of ISS_049IA_FP1NITMAP001_CIRS prior to a large RADAR SAR data set from the dark side.

ICYEXO003_UVIS
=========
http://saturn.jpl.nasa.gov/multimedia/imag...iImageID=126232
(I presume the bright spot near the center of the image is Nunki or Sigma Sagittari)

ICYMAP003_UVIS
=========
http://saturn.jpl.nasa.gov/multimedia/imag...3/N00091840.jpg
http://saturn.jpl.nasa.gov/multimedia/imag...3/N00091841.jpg
http://saturn.jpl.nasa.gov/multimedia/imag...3/N00091842.jpg

FP1NITMAP001_CIRS
=========
http://saturn.jpl.nasa.gov/multimedia/imag...3/N00091839.jpg
http://saturn.jpl.nasa.gov/multimedia/imag...iImageID=126231

So we got a little bit more than we expected.

This surface makes most of Earth's moon look young....



P

Yeah... ...doesn't look like it ever had anything in the way of a major resurfacing event like the lunar maria, ever, at least the terrain we've seen. Think that exogenic origin of the splotch is looking more likely now...

Anyone else find these close-ups oddly evocative of Phoebe?

Good catch, antipode. I was so caught up in the wonder of the encounter that I somehow managed to miss that.

I don't know about anyone else, but in some of these images I'm seeing very definite evidence of material flow, in a direction that, if the shadows aren't playing tricks on me, seems parallel to Iapetus' orbital motion.

In other words, it looks a lot to me like most of the larger craters have debris on opposite sides, filling in both inner walls to some degree but piled up a bit more on the far sides (in relation to their orientation towards the direction of orbital motion). The debris patterns seem to consistently apply themselves 180 degrees apart on the larger crater rims (i.e., the thickest or most obvious sections of the debris accumulations lie approximately 180 degrees apart along the rims), and the vector through these points in the crater walls seem to align with direction of orbital motion.

I'm getting my concept of the direction of orbital motion from the shadow angles and from my (admittedly extremely rough) concept of where these regions lie in relation to the equatorial ridge. In any event, to make it a little simpler, it looks like the vector defined by the 180-degree-seperated rim distortions points back toward the center of Cassini Regio, i.e., towards the center of the region Iapetus that faces into its direction of orbital motion.

It will be more instructive, and prove more, when I can see exactly where these images are located and where those vectors actually point. After all, you *could* (and, on many Solar System bodies, do) see the same kind of phenomenah emanating from basins. But while some of this looks like ejecta, more of it looks like, well -- duning. To me.

This debris accumulation looks less obvious in the inter-crater "plains" (as rare as they seem to be) than on the rims and floors of the larger craters. But I really do think I see very specific patterns of debris accumulation here. It would seem to support the belief that material is, or has been at some point in the past, very slowly "flowing" from the midpoint of Cassini Regio out in vectors away from the leading face's central point. What's harder to tell is whether the "flow" is more radial to the center of the leading face, or more parallel to the equatorial ridge. It may well be a combination of the two...

I'd have to say it looks like the surface is very ancient, but that that the debris accumulations (which you don't see in such abundance on the other icy moons), while relatively thin in most places, seem to definitely overlay almost all of the craters to the same extent. In other words, this material is younger than the underlying ancient surface, but thin enough that it doesn't resurface the ancient terrain, it just piles dunes and sprays of debris on top of it. It's not enough material to resurface, but it does seem to be enough material to "paint" the cratered terrain a very dark brown.

-the other Doug

dvandorn, I'll have to look at these images again to see what you are talking about. Any chance you can draw up something in Paint or Photoshop to illustrate what you are talking about?

To me, these images tell the tale of a very ancient world. The surface is very heavily cratered. We do do see some relatively young craters (don't ask me for an age estimate) with flat floors, central peaks, and mild to major slumping along crater walls. We also see some very ancient craters that have been eroded by later impacts, which have ruggidized the crater floors and space weathering, which has smoothed out many of the earlier hummocks produced from slumping.

From the images that have been returned so far, expect the highest resolution images to show a relatively smooth surface with impact craters down to the limit of resolution, though it maybe interesting to see if the dark material deposition has buried some of the smallest impact craters. This would be evidenced of course by a lower limit to impact crater size. Could be interesting to see. I don't expect the kind of bouldery surface we saw at Enceladus.

The distribution (size and number) of smaller craters (if that's what they are) in the inter-crater "plains" appear odd. There appears to be some number of craters of one narrow size range, with very few or none that are, say, twice as large and larger, or half as large and smaller. At first glance, they appeared to be a smattering of huge boulders.

<beats his head on the keyboard in frustration>

When, did somebody say, is the next batch of pictures likely to be posted?