Hi,
CASSINI has transmitted 184 pics (!) over the last days.
Here five takeouts, 3-4x enlargement:
Click to view attachment
Date: 2009-09-06
Distance: 2.228.548 km
Filters: CL1 and CL2
Click to view attachment
Date: 2009-09-08
Distance: 3.215.284 km
Filters: P120 and GRN
Click to view attachment
Date: 2009-09-08
Distance: 3.216.610 km
Filters: P60 and GRN
Click to view attachment
Date: 2009-09-09
Distance: 3.390.271km
Filters: P60 and GRN
Click to view attachment
Date: 2009-09-09
Distance: 3.427.313 km
Filters: P120 and GRN
Maybe somebody is able to combine some of those images to show more details.
Bye.
Full Version: New Iapetian image series
Unmanned Spaceflight.com > Outer Solar System > Saturn > Cassini Huygens > Cassini's ongoing mission and raw images
They certainly took enough images this time around. There must be at least a hundred new ones.
[Edit: oops, 184; didn't read the above post carefully the first time.]
[Edit: oops, 184; didn't read the above post carefully the first time.]
At the end of November, Cassini will be a bit over two million kilometres from Iapetus. That hardly even qualifies as a "distant encounter" -- it's really just plain "distant".
Nonetheless, looking at the Solar System Simulator for dates around November 25th, any images taken around this time will probably be nice to look at, because they should show a bit more of the trailing, light-coloured part of the Saturn-facing hemisphere, Roncevaux Terra, than we have seen before. (Of course, we've seen some of it relatively close-up in Saturnshine during the New Year's 2005 distant flyby.) Cassini will be near apastron then, so there should be a bit of free time for taking pictures of Iapetus.
We haven't seen much of this part of Iapetus in previous Cassini images. My impression (correct me if I'm wrong) is that this is due to the geometry of Cassini's orbit around Saturn, up to the present time. Whenever Cassini is well placed to photograph the trailing side of Iapetus, it will normally also be very close to Saturn, which means that other things would naturally take priority over getting fuzzy pictures of a moon three million kilometres away.
Nonetheless, looking at the Solar System Simulator for dates around November 25th, any images taken around this time will probably be nice to look at, because they should show a bit more of the trailing, light-coloured part of the Saturn-facing hemisphere, Roncevaux Terra, than we have seen before. (Of course, we've seen some of it relatively close-up in Saturnshine during the New Year's 2005 distant flyby.) Cassini will be near apastron then, so there should be a bit of free time for taking pictures of Iapetus.
We haven't seen much of this part of Iapetus in previous Cassini images. My impression (correct me if I'm wrong) is that this is due to the geometry of Cassini's orbit around Saturn, up to the present time. Whenever Cassini is well placed to photograph the trailing side of Iapetus, it will normally also be very close to Saturn, which means that other things would naturally take priority over getting fuzzy pictures of a moon three million kilometres away.
I just used the Solay System simulator and I have the following:
Date: November 27, 2006
Time: 00 hours (UT)
Distance: 2.008 million km
A full disk view of the Saturn facing hemisphere of Iapetus at 12km/pxl
I'm sure with multiple images and super ehancement, we can fill in a imaging gap of Iapetus
in the high northern latitudes at better than the 9km/pxl that Voyager 2 achived in 1981.
Date: November 27, 2006
Time: 00 hours (UT)
Distance: 2.008 million km
A full disk view of the Saturn facing hemisphere of Iapetus at 12km/pxl
I'm sure with multiple images and super ehancement, we can fill in a imaging gap of Iapetus
in the high northern latitudes at better than the 9km/pxl that Voyager 2 achived in 1981.
Hi,
here what you're talking about:
Click to view attachment
Should give some more additional information about northern Roncevaux Terra as well as a nice view of the 'Snowman'.
Bye.
here what you're talking about:
Click to view attachment
Should give some more additional information about northern Roncevaux Terra as well as a nice view of the 'Snowman'.
Bye.
I can't wait to see that!
[something went wrong here]
I created the same image with Xplanet and Steve Albers' map:
Click to view attachment
As you can see, it doesn't really cover any lands we haven't seen before..
Click to view attachment
As you can see, it doesn't really cover any lands we haven't seen before..
QUOTE (CAP-Team @ Sep 25 2006, 05:56 AM) 
As you can see, it doesn't really cover any lands we haven't seen before..
Maybe not, but it will give us a chance to see some familiar territory from a different lighting angle. This will also be the case during the three remaining 2-million-kilometre flybys (around Feb 11th, Apr 15 and Jul 5) before the close-up view a year from now.
I think it's during the February encounter that we will see sunrise on "Snowman" over the course of several days -- instead of sunset, which has usually been the case. That should be of some significance for people who are interested in the "moat" (even though, at that distance, we'll hardly be able to see any detail).
I think that super-resolution processing may be needed to pull any nice looking images out of this. But that would have to wait for the PDS release (Stacking the "raw" jpegs will help compensate for compression artifacts, but does litttle else to improve resolution.
QUOTE (Rob Pinnegar @ Sep 25 2006, 01:56 PM)
2-million-kilometre flybys
Now that just sounds silly!
QUOTE (tedstryk @ Sep 25 2006, 03:11 PM)
I think that super-resolution processing may be needed to pull any nice looking images out of this. But that would have to wait for the PDS
So in 12 months time or so we'll get to unleash our image processing skills on a few 2 million km distant frames... By that time the 1500 km flyby will be over and noone will even look back at these puny frames!
QUOTE (Rob Pinnegar @ Sep 25 2006, 01:56 PM)
Maybe not, but it will give us a chance to see some familiar territory from a different lighting angle.
This will also be the case during the three remaining 2-million-kilometre flybys (around Feb 11th, Apr 15 and Jul 5)
before the close-up view a year from now.
I think it's during the February encounter that we will see sunrise on "Snowman" over the course of several days
- instead of sunset, which has usually been the case.
That should be of some significance for people who are interested in the "moat"
(even though, at that distance, we'll hardly be able to see any detail).
This will also be the case during the three remaining 2-million-kilometre flybys (around Feb 11th, Apr 15 and Jul 5)
before the close-up view a year from now.
I think it's during the February encounter that we will see sunrise on "Snowman" over the course of several days
- instead of sunset, which has usually been the case.
That should be of some significance for people who are interested in the "moat"
(even though, at that distance, we'll hardly be able to see any detail).
The april and july far-encounters will show some other details in different lightning angle:
Click to view attachmentClick to view attachment
The later one will probably show some parts of the mostly unknown great southern bassin.
Bye.
Hi again,
new release in the NASA/JPL image gallery - 'Duotone Moon':
Date: 2006-09-06
Distance: ~2.2 mio km
Resolution: 13 km/pxl
Bye.
new release in the NASA/JPL image gallery - 'Duotone Moon':
Date: 2006-09-06
Distance: ~2.2 mio km
Resolution: 13 km/pxl
Bye.
I used NASA's space simulator a lot in the past, but I think their maps aren't quite as good as Steve Albers' maps.
Click to view attachment Click to view attachment
The view of July is finally giving us a view of unexplored terrain, just prior to the close encounter of september 2007.
Really looking forward to that.
Click to view attachment Click to view attachment
The view of July is finally giving us a view of unexplored terrain, just prior to the close encounter of september 2007.
Really looking forward to that.
As TritonAntares said, the key is that the illumination conditions will be different. This "flyby" may be useful for albedo mapping.
QUOTE (CAP-Team @ Sep 25 2006, 04:20 PM)
The view of July is finally giving us a view of unexplored terrain, just prior to the close encounter of september 2007.
Really looking forward to that.
Really looking forward to that.
Yeah, that area was imaged in August 2004, but from so far away (10 million kilometres) that the only details visible were the basic outline of the Roncevaux Terra basin, and its central peak. So, although we *have* seen it, it's effectively unexplored.
The LPSC 2005 abstract by Denk et. al., "The first six months of Iapetus observations by the Cassini ISS camera", shows processed versions of these images. It's online and is easily located with a Google search. (Don't bother checking the raw images from August 2004 -- you can't see anything in those.) This gives a good idea of the size of that basin. It's about the same size as the huge one on the Saturn-facing side.
Hi!
I've looked through the images of this period and probably found some of those you meant.
Here a takeout:
Click to view attachment
Date: 2004-07-22
Distance: 3.489.136 km
Filters: CL1 and CL2
Difficult to say wether it's the western rim of the large southern bassin in Roncevaux Terra at the terminator.
This chart could be helpful:
Click to view attachment
The eastern rim of the bassin is nice in this pics from October 2004:
Bye.
QUOTE
Yeah, that area was imaged in August 2004, but from so far away (10 million kilometres) that the only details visible
were the basic outline of the Roncevaux Terra basin, and its central peak.
So, although we *have* seen it, it's effectively unexplored.
were the basic outline of the Roncevaux Terra basin, and its central peak.
So, although we *have* seen it, it's effectively unexplored.
I've looked through the images of this period and probably found some of those you meant.
Here a takeout:
Click to view attachment
Date: 2004-07-22
Distance: 3.489.136 km
Filters: CL1 and CL2
Difficult to say wether it's the western rim of the large southern bassin in Roncevaux Terra at the terminator.
This chart could be helpful:
Click to view attachment
The eastern rim of the bassin is nice in this pics from October 2004:
Bye.
The lower left image is the same as the one I made a while ago, using stretched color, but toned down to better match the approximate true color. The contrast is stronger in my composite so darker details aren't very visible, though: Iapetus in color.
There's also the CICLOPS release showing the same image sequence in stretched color.
There's also the CICLOPS release showing the same image sequence in stretched color.
Hi!
CASSINI took another few Iapetus images about 10 days ago,
here 3 of them:
Click to view attachment
Date: 2004-09-18, 20 and 21
Distance: 2.359.595 / 2.486.163 / 2.517.820 km
Filters: CL1 and CL2
Nice sunset out there...
Bye.
CASSINI took another few Iapetus images about 10 days ago,
here 3 of them:
Click to view attachment
Date: 2004-09-18, 20 and 21
Distance: 2.359.595 / 2.486.163 / 2.517.820 km
Filters: CL1 and CL2
Nice sunset out there...
Bye.
That recent small sequence is really striking to me; Iapetus looks a lot like a CD or DVD! 
In fact...is this significant or coincidental?
It looks like the dark area subtends a suspiciously well-defined angular area in this view (90 deg of the total spherical area of Iapetus?), which in turn would seem to argue for external deposition from some source. In any case, the geometry of the dark area is remarkable.
In fact...is this significant or coincidental?
It looks like the dark area subtends a suspiciously well-defined angular area in this view (90 deg of the total spherical area of Iapetus?), which in turn would seem to argue for external deposition from some source. In any case, the geometry of the dark area is remarkable.
I suspect a thermo-reactive gas is introduced into the Iapetan environment at a fixed point in its' orbit about Saturn. Most likely when Iapetus traverses the Saturnian magnetotail.
The gas persists in the vicinity of Iapetus, and in equatorial to the midlatitudes the Iapetan surface temperatures are sufficient for the gas to 'tholinize' and coat the surface. The gas is used up (or dissipates into the void) in less than the ~80 days it takes for Iapetus to return to the place in it's orbit where the gas is replenished, thus, we do not see the darkening extending further around in longitude than we do.
That there is some 'ponding' of the gas in low areas seems apparent, there is some darkening outside of the main areal extent of Cassini Regio in the lower latitudes.
Additionally, the more directly perpendicularly sunward facing segments of crater bowls north and south of Cassini Regio also show the darkening, as expected, the local heating conditions being sufficient for the chemical staining reaction to occur.
The gas also appears to interact with Hyperion. Quantities of it appear to pond in the craters, and when the chaotic rotation of Hyperion causes the sun to shine perpendicularly into a given crater, the crater bowl reflects enough solar radiation onto the crater floor to make a local warm spot. The gas reacts, and we get dark crater bottoms all over Hyperion.
The same basic mechanism, a thermo-reactive gas being introduce into the Hyperionian and Iapetan environments, explains the dark areas of each moon.
The gas persists in the vicinity of Iapetus, and in equatorial to the midlatitudes the Iapetan surface temperatures are sufficient for the gas to 'tholinize' and coat the surface. The gas is used up (or dissipates into the void) in less than the ~80 days it takes for Iapetus to return to the place in it's orbit where the gas is replenished, thus, we do not see the darkening extending further around in longitude than we do.
That there is some 'ponding' of the gas in low areas seems apparent, there is some darkening outside of the main areal extent of Cassini Regio in the lower latitudes.
Additionally, the more directly perpendicularly sunward facing segments of crater bowls north and south of Cassini Regio also show the darkening, as expected, the local heating conditions being sufficient for the chemical staining reaction to occur.
The gas also appears to interact with Hyperion. Quantities of it appear to pond in the craters, and when the chaotic rotation of Hyperion causes the sun to shine perpendicularly into a given crater, the crater bowl reflects enough solar radiation onto the crater floor to make a local warm spot. The gas reacts, and we get dark crater bottoms all over Hyperion.
The same basic mechanism, a thermo-reactive gas being introduce into the Hyperionian and Iapetan environments, explains the dark areas of each moon.
That is both an interesting and highly creative hypothesis, Tasp. Skeptical questions must follow, though:
1. What is the nature of this thermoreactive gas? I presume that it is being scattered off of Saturn's upper atmosphere somehow.
2. Why do no other moons but Iapetus & Hyperion exhibit any apparent effects from this environmental condition? Probable minor compositional differences do not seem adequate. Additionally, this thermoreactive agent would presumably have a relatively high molecular weight, and therefore its transport throughout the region would not necessarily be confined to the outer limits of Saturn's magnetosphere in accordance with magnetic current flow patterns.
Sorry; I am not trying to put you on the spot at all...just trying to flesh out this most interesting thought of yours, which would have never occurred to me!
1. What is the nature of this thermoreactive gas? I presume that it is being scattered off of Saturn's upper atmosphere somehow.
2. Why do no other moons but Iapetus & Hyperion exhibit any apparent effects from this environmental condition? Probable minor compositional differences do not seem adequate. Additionally, this thermoreactive agent would presumably have a relatively high molecular weight, and therefore its transport throughout the region would not necessarily be confined to the outer limits of Saturn's magnetosphere in accordance with magnetic current flow patterns.
Sorry; I am not trying to put you on the spot at all...just trying to flesh out this most interesting thought of yours, which would have never occurred to me!
The gas comes from Titan's atmosphere. This implies only objects exterior to Titan's orbit will experience the darkening as there is no transport mechanism running from Titan inward.
The atmospheric gases of Titan contain carban and nitrogen and hydrogen. The thermosensitive chemical reaction (way out of my schooling here) might be a polymerization of those Titanian gases. I suspect the orange color of Titan and the rich brown of Iapetus are derived from similar compounds and elements.
I don't know if slow steady leakage of atmospheric gases from Titan is what is happening, or if big impact events on Titan liberate gases sporadically.
Maybe both processes have occured over the history of the solar system.
The atmospheric gases of Titan contain carban and nitrogen and hydrogen. The thermosensitive chemical reaction (way out of my schooling here) might be a polymerization of those Titanian gases. I suspect the orange color of Titan and the rich brown of Iapetus are derived from similar compounds and elements.
I don't know if slow steady leakage of atmospheric gases from Titan is what is happening, or if big impact events on Titan liberate gases sporadically.
Maybe both processes have occured over the history of the solar system.
Hi!
CASSINI took another few Iapetus far distance images 3 days ago,
here a takeout:
Click to view attachment
Date: 2006-11-05
Distance: 4.438.289 km
Filters: CL1 and CL2
View with Solar System Simulator:
Click to view attachment
By the end of this month we'll get a nice view from about 2 mio. km:
Click to view attachment
Click to view attachment
Finally a little change in the angle of view....
Bye.
CASSINI took another few Iapetus far distance images 3 days ago,
here a takeout:
Click to view attachment
Date: 2006-11-05
Distance: 4.438.289 km
Filters: CL1 and CL2
View with Solar System Simulator:
Click to view attachment
By the end of this month we'll get a nice view from about 2 mio. km:
Click to view attachment
Click to view attachment
Finally a little change in the angle of view....
Bye.
Here's the simulated pixel size Iapetus will appear on Nov 27. Obviously not that useful except for low phase observations.
Hi once again,
CASSINI took another four Iapetus far distance images,
here a takeout:
Click to view attachment
Date: 2006-11-16
Distance: 3.128.691 km
Filters: CL1 and CL2
View with Solar System Simulator:
Click to view attachment
We're getting 'closer'...
Bye.
CASSINI took another four Iapetus far distance images,
here a takeout:
Click to view attachment
Date: 2006-11-16
Distance: 3.128.691 km
Filters: CL1 and CL2
View with Solar System Simulator:
Click to view attachment
We're getting 'closer'...
Bye.
Hi,
CASSINI took a series of 41 Iapetean far distance pics yesterday,
here a first takeout:
Click to view attachment
Date: 2006-11-27
Distance: 1.997.980 km
Filters: CL1 and CL2
There's an interesting dark feature east (right) of the 'Snowman'.
View with Solar System Simulator:
Click to view attachment
Part of Steve Albers map:
Click to view attachment
The mentioned dark structure contains at least one crater with a dark ground.
Bye.
CASSINI took a series of 41 Iapetean far distance pics yesterday,
here a first takeout:
Click to view attachment
Date: 2006-11-27
Distance: 1.997.980 km
Filters: CL1 and CL2
There's an interesting dark feature east (right) of the 'Snowman'.
View with Solar System Simulator:
Click to view attachment
Part of Steve Albers map:
Click to view attachment
The mentioned dark structure contains at least one crater with a dark ground.
Bye.
Hello again,
I always wondered about the dark patches in Iapetus' bright region Roncevaux Terra as seen on this map:
Click to view attachment
The left part is illuminated by saturnlight, the right part is made up of VOYAGER findings.
The mentioned dark feature east (right) of the 'Snowman' contains at least one crater with a dark ground.
But what about the dark markings on the bad resolved VOYAGER side?
Are these mostly shadowing effects like the craters in the northern hemisphere presume or real dark patches like the 'horseshoe' next to the border of the saturnlighted part or the black triangle and the spots around it?
Actually the triangle partly seems to overspread an underlying not so dark area...
Some ideas?
Bye.
I always wondered about the dark patches in Iapetus' bright region Roncevaux Terra as seen on this map:
Click to view attachment
The left part is illuminated by saturnlight, the right part is made up of VOYAGER findings.
The mentioned dark feature east (right) of the 'Snowman' contains at least one crater with a dark ground.
But what about the dark markings on the bad resolved VOYAGER side?
Are these mostly shadowing effects like the craters in the northern hemisphere presume or real dark patches like the 'horseshoe' next to the border of the saturnlighted part or the black triangle and the spots around it?
Actually the triangle partly seems to overspread an underlying not so dark area...
Some ideas?
Bye.
I would not know either. But we will know alot better after September 10, 2007 when Cassini will image this area with resolution as good as 200m per pixel!
Hi,
nice pic Phil - I didn't notice the 2 originals on the JPL/NASA page at all.
It'll may help to measure the depth of Snowman A and the hight of its central peak...
Have you tried to combine some of the Nov.27th images, probably getting some colored ones?
Bye.
nice pic Phil - I didn't notice the 2 originals on the JPL/NASA page at all.
It'll may help to measure the depth of Snowman A and the hight of its central peak...
Have you tried to combine some of the Nov.27th images, probably getting some colored ones?
Bye.
Hallo,
one probably better resolved and enlarged pic of the last far-encounter is on the JPL/NASA page.
Date: 2006-11-27
Distance: ~2 mio km
Resolution: 12 km/pixel
Sadly no color composite...
Bye.
one probably better resolved and enlarged pic of the last far-encounter is on the JPL/NASA page.
Date: 2006-11-27
Distance: ~2 mio km
Resolution: 12 km/pixel
Sadly no color composite...
Bye.
QUOTE (TritonAntares @ Jan 9 2007, 11:49 AM)
Sadly no color composite...
Me, I've stopped expecting color composites altogether. It's as though they're taboo for the team. That said, they do manage to pull off a good sharpening/deconvolution job on the grayscales.
Is Roland the prominent crater at the 11 o'clock position?
My version made from one RVB picture (saturation at 200%) and 10 b&w stacked and added pictures. 200% approx. size.
Pink Iapetus, now that's something you don't see every day!
QUOTE (Rob Pinnegar @ Feb 14 2007, 02:34 AM)
Click to view attachment
Is Roland the prominent crater at the 11 o'clock position?
Iapetus northern hemisphere:Is Roland the prominent crater at the 11 o'clock position?
Click to view attachment
Click to view attachment
Seems to be Roland due to its position and the large central peak.
But be careful, there are 4 prominent craters in this region - one at the bright-dark border ...
Bye.
QUOTE (Rob Pinnegar @ Feb 13 2007, 08:34 PM)
Is Roland the prominent crater at the 11 o'clock position?
Yes. Here's the Voyager-based map showing the Saturn-facing hemisphere of Iapetus, which closely matches this image. Roland is at the top.
Michael
ugordan: "Pink Iapetus, now that's something you don't see every day!"
It's a Valentine!
Phil
It's a Valentine!
Phil
QUOTE (ugordan @ Feb 14 2007, 03:16 AM)
Pink Iapetus, now that's something you don't see every day!
This could turn into a drug-related discussion...
QUOTE (JRehling @ Feb 14 2007, 06:08 PM)
This could turn into a drug-related discussion...
You mean something like: "There are no bad drugs. Just bad trips." ?
Huh...that "yin-yang" aspect makes Iapetus look like one of the hemispherical views of Fritz Leiber's The Wanderer...art imitating life in yet another subtle way, albeit decades in advance.
Just struck me also how deep & pronounced all these craters are in comparison to those on the inner large icy moons. Is this difference perhaps due to fallout from Enceladus on the latter, as discussed on another thread, or are we seeing evidence of a thicker crust on Iapetus?
Just struck me also how deep & pronounced all these craters are in comparison to those on the inner large icy moons. Is this difference perhaps due to fallout from Enceladus on the latter, as discussed on another thread, or are we seeing evidence of a thicker crust on Iapetus?
QUOTE (nprev @ Feb 14 2007, 03:25 PM)
Huh...that "yin-yang" aspect makes Iapetus look like one of the hemispherical views of Fritz Leiber's The Wanderer...art imitating life in yet another subtle way, albeit decades in advance.
Just struck me also how deep & pronounced all these craters are in comparison to those on the inner large icy moons. Is this difference perhaps due to fallout from Enceladus on the latter, as discussed on another thread, or are we seeing evidence of a thicker crust on Iapetus?
Just struck me also how deep & pronounced all these craters are in comparison to those on the inner large icy moons. Is this difference perhaps due to fallout from Enceladus on the latter, as discussed on another thread, or are we seeing evidence of a thicker crust on Iapetus?
Remembering that Iapetus is a startling outlier (literally and figuratively) in terms of its distance from its primary (only likely captured asteroids rival it among the natural satellites in the solar system), I suggest that its distance is the prime causative factor.
Look at the crusts of Mercury and the Moon and the Moon's maria. They are all three "old". The oldest crust there is not much more than 25% older than the youngest. But the rate of cratering is profoundly different: The cratering rate changed so sharply around 4 GYA that relatively minor differences in age led to tremendous differences in the preserved-for-all-time proportions of craters left behind.
I think the difference between Iapetus on the one hand and Rhea on the other (virtually identical size and distance from the Sun) is that the heat of proto-Saturn kept Rhea slushy just a bit longer, letting its primordial lumps from coalescing round out and its largest proto-impacts to fade into the slush. Iapetus cooled faster and has kept its original lumps in a way that no body outside the asteroid belt could have because all the planets are too large and all the other midsize satellites are too close to their primaries.
As a result, Ceres and Iapetus are less spherical than Rhea, Titania, and Oberon, and even some of the smaller icy satellites of Saturn and Uranus.
The large craters are just another manifestation of the big, early impacts having been left untouched by any general crustal slushiness during that period.
QUOTE (nprev @ Feb 14 2007, 05:25 PM)
or are we seeing evidence of a thicker crust on Iapetus?
To extend this discussion, consider Iapetus accreting from the primordial chaos. Iapetus (or more accurately, the proto-Iapetus) pokes along in its' orbit at 5000 KPH (or was it MPH? no matter) and takes ~80 days to loop around Saturn. Its' accretion process took much longer than any other 'big time' satellite in the solar system. During this longer coalescense, the Al27 in the incoming materials had longer to radiate its' heat to space, and Iapetus had longer to radiate the collisional heating from impacts that formed it. Iapetus will be the satellite most accurately we can describe as cold formed. The crust will have enormous bearing strength. As we saw in the Cassini pix, the lumpy, facety surface of Iapetus exists to this day. The 'cat scratch' feature (IIRC, SW of 'landslide crater') might record an extremely deep penetration into the solid body of Iapetus by the impactor that made the 'landslide basin'.
Assuming a formation via external agency of the equatorial ridge structure long after Iapetus accreted, the structure rests on the surface, is 20 km high (60,000+ feet high!!!), and to date, in the Cassini photos, we see no faulting parallel to the ridge.
Additionally, to date, we see no signs of volcanism, past or present, no geysers, plumes, mud pots or warm spots. Internal heat sources have been inoperative at 'softening' the crust for a very long time.
Something else reducing the heating to the interior of Iapetus ids it's distance from Saturn. Granted, Iapetus is tide locked to Saturn today, but of all the major satellites in the solar system, tidal braking of Iapetus was uniquely slow. Any power dissipated this way had ample time to radiate away in the cryogenic environment, to no or little effect.
Hi,
I've just checked the JPL raw images page for new iapetean pics - and was successful:
189 new images between Feb.12th and 16th (!)
Looks like there has been a shadow casting show by saturn during this time on Iapetus...
Here some takeouts:
Click to view attachment
Date: 2007-02-13
Distance: 2.269.440 km
Filters: CL1 and CL2
4x enlarged
Click to view attachment
Date: 2007-02-13
Distance: 2.267.233 km
Filters: CL1 and CL2
4x enlarged
Click to view attachment
Date: 2007-02-13
Distance: 2.264.177 km
Filters: CL1 and CL2
4x enlarged
Click to view attachment
Date: 2007-02-14
Distance: 2.248.671 km
Filters: CL1 and GRN
4x enlarged
Click to view attachment
Date: 2007-02-14
Distance: 2.248.666 km
Filters: CL1 and CL2
4x enlarged
Click to view attachment
Date: 2007-02-14
Distance: 2.248.655 km
Filters: CL1 and UV3
4x enlarged
Click to view attachment
Date: 2007-02-15
Distance: 2.322.227 km
Filters: P120 and MT2
4x enlarged
Have a view at the whole images series and you will recognize a migrating shadow on Feb.13/14th,
maybe somebody can affim an iapetean eclipse using some simulation program?!
Bye.
I've just checked the JPL raw images page for new iapetean pics - and was successful:
189 new images between Feb.12th and 16th (!)
Looks like there has been a shadow casting show by saturn during this time on Iapetus...
Here some takeouts:
Click to view attachment
Date: 2007-02-13
Distance: 2.269.440 km
Filters: CL1 and CL2
4x enlarged
Click to view attachment
Date: 2007-02-13
Distance: 2.267.233 km
Filters: CL1 and CL2
4x enlarged
Click to view attachment
Date: 2007-02-13
Distance: 2.264.177 km
Filters: CL1 and CL2
4x enlarged
Click to view attachment
Date: 2007-02-14
Distance: 2.248.671 km
Filters: CL1 and GRN
4x enlarged
Click to view attachment
Date: 2007-02-14
Distance: 2.248.666 km
Filters: CL1 and CL2
4x enlarged
Click to view attachment
Date: 2007-02-14
Distance: 2.248.655 km
Filters: CL1 and UV3
4x enlarged
Click to view attachment
Date: 2007-02-15
Distance: 2.322.227 km
Filters: P120 and MT2
4x enlarged
Have a view at the whole images series and you will recognize a migrating shadow on Feb.13/14th,
maybe somebody can affim an iapetean eclipse using some simulation program?!
Bye.
No way! Mega cool!
Stretched color snapshots at the start and near maximum eclipse:
Click to view attachment
So... Saturn really is yellow. Who would have known!
Stretched color snapshots at the start and near maximum eclipse:
Click to view attachment
So... Saturn really is yellow. Who would have known!
Way nifty. Here's an animation of the February 14 set, magnified 2x. Note that since this is during an eclipse, the ones that aren't in eclipse are necessarily pretty much zero phase.
Click to view attachment
Those of you who've worked more with making the raw JPEGs pretty, can you suggest improvements?
--Emily
Click to view attachment
Those of you who've worked more with making the raw JPEGs pretty, can you suggest improvements?
--Emily
Actually, not necessarily zero phase. Remember this isn't the case where the observer is located on the body that's casting the shadow. I get a 14.5 degree phase from Cassini's vantage point at Feb 14, 02:00 UTC
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