http://saturn.jpl.nasa.gov/news/features/feature20060915.cfm
Ring scientists have been waiting for this. Finally, after more than two years orbiting Saturn, the Cassini spacecraft reaches one of the ultimate vantage points. The rings should shine with majesty worthy of the "Jewel of the Solar System."
It doesn't say, but the Solar System Simulator shows the occultation - of the planet, not the rings - occurring from about 7:00 UTC to 23:00 UTC on the 15th, which is 3:00 AM EDT -7:00 PM EDT on the 15th. And it does say the images will be sent to Earth on the 17th. They should be spectacular!
I am looking forward to this one too.
Another interesting thing about this set of observations is that, given the long exposure times needed to bring out details in the D, G and E rings, we're probably going to see the inner planets in some of the images. Earth, and especially Venus, will be easiest; each should fill up about a fifth of a pixel (in the wide angle camera).
As luck would have it, the Moon was almost at its greatest elongation from Earth, as seen from Saturn, on September 15th. Seen through the wide-angle camera, it should be about four pixels away from the Earth, and about four magnitudes fainter. I wonder if it will be visible? Guess it will depend on the amount of smearing due to spacecraft motion (which, now that I think of it, would likely cause the Earth to overwrite the Moon anyways).
First images are now posted, including some remarkable, though overexposed, http://saturn.jpl.nasa.gov/multimedia/images/raw/raw-images-details.cfm?feiImageID=83138 of sunset behind Saturn...
Shouldn't this thread be moved to the Cassini subforum?
John.
Amazing how bright the "gap" between the outer edge of A ring and the F ring is http://saturn.jpl.nasa.gov/multimedia/images/raw/raw-images-details.cfm?feiImageID=83182. The F ring is brilliant and the Encke gap is notably dusty as well.
It's a shame a vast sequence of Saturn's limb, multi-filter frames got severly overexposed and suffers from charge bleeding. Hopefully the wide-angles will turn out better.
http://saturn.jpl.nasa.gov/multimedia/images/raw/raw-images-details.cfm?feiImageID=83406 - Earth (just below the A-ring ansa), Enceladus+plume (upper right), and the E and G rings, as well as the main ring system! North is at the bottom.
John.
Spokes in the E-ring?
http://saturn.jpl.nasa.gov/multimedia/images/raw/casJPGFullS23/W00018033.jpg
http://saturn.jpl.nasa.gov/multimedia/images/raw/casJPGFullS23/W00018036.jpg
Enceladus in the E-ring
http://saturn.jpl.nasa.gov/multimedia/images/raw/casJPGFullS23/W00018011.jpg
E-ring distorted by Enceladus
http://saturn.jpl.nasa.gov/multimedia/images/raw/casJPGFullS23/W00017915.jpg
Diamond ring effect
http://saturn.jpl.nasa.gov/multimedia/images/raw/casJPGFullS23/W00017924.jpg
http://saturn.jpl.nasa.gov/multimedia/images/raw/raw-images-list.cfm?StartRow=33&cacheQ=1&browseLatest=1&storedQ=1318192.
http://saturn.jpl.nasa.gov/multimedia/images/raw/raw-images-details.cfm?feiImageID=83417.
The stitched/processed HDR version of this image set is going to be utterly spectacular. My thanks to all involved in the mission for the amazing images and the opportunity for nerds like me to see them when they come down.
okay, this one requires an explanation:
http://saturn.jpl.nasa.gov/multimedia/images/raw/casJPGFullS23/W00018018.jpg
The dynamic range involved in trying to capture the 'halo', the lit rings, and the E ring makes it almost impossible to capture in one image - but this is my best guess.
I see that the sequence made the effort to do multiple exposures in each filter set - but there was some down-sampling in some of the exposures. When this lot hits the PDS I'm sure Bjorn et al will work wonders on it Vio+IR is just enough to make something interesting
By explanation - would it be enough to say that just about everything is saturated and scattering of light from the rings is lighting the 'eclipsed' rings as well?
Doug
http://saturn.jpl.nasa.gov/multimedia/images/raw/raw-images-details.cfm?feiImageID=83319
http://saturn.jpl.nasa.gov/multimedia/images/raw/raw-images-details.cfm?feiImageID=83226
Note : we see clearly the shadow of the secondary miror of the objective of the camera on the first pic.
In http://saturn.jpl.nasa.gov/multimedia/images/raw/raw-images-details.cfm?feiImageID=83137, what's the overexposed elliptical feature inside the limb? Is it an artifact?
It couldn't be a highly-refracted image of the Sun's disc, could it? (I assume not -- isn't that what the continuous ring all the way around the limb is, effectively?)
In neighbouring images (which I guess let more light in) the same region bleeds vertically (http://saturn.jpl.nasa.gov/multimedia/images/raw/raw-images-details.cfm?feiImageID=83138, http://saturn.jpl.nasa.gov/multimedia/images/raw/raw-images-details.cfm?feiImageID=83139, http://saturn.jpl.nasa.gov/multimedia/images/raw/raw-images-details.cfm?feiImageID=83140).
Why would they downsample all the images to 512x512 or less?
EDIT: OK I found one that I hoped would be full size:
http://saturn.jpl.nasa.gov/multimedia/images/raw/raw-images-details.cfm?feiImageID=83290
http://saturn.jpl.nasa.gov/multimedia/images/raw/raw-images-details.cfm?feiImageID=83288
Tethys's shadow is visible in the E-ring
Is this a new (albeit very faint) ring between the F and G rings?
Wow!!!!!
It occurs to me that if we had gotten images from this vantage point early in the orbital phase of the mission, there would have been no doubt whatsoever that Enceladus is the source of the E ring. You can see the ring material flowing off of Enceladus and smoothing itself into the ring quite clearly.
Amazing, amazing images. As someone said nearly 40 years ago of a somewhat similar view of the Moon, it's worth the price of the trip.
-the other Doug
Hi,
wow really impressive pics!!!
Does anybody know a link for a larger version of this overview...
...of the mosaik?
I'm just asking for indentification purposes of all these objects around Saturn - its moons and the visible 'inner planets'.
THX & Bye.
Two pictures to add into this spectacular Cassini gallery.
Sun eclipse by Saturn at different exposures :
Ant103, great work!
Is really a little science fiction rendering!
If I'm not wrong, in the second (coulor) image I see some bright, long features inside the Enke division...
Do someone has any idea on their origin?
I believe the bright spot above the E-ring in the first image and above the G-ring in the second image is the Earth
http://saturn.jpl.nasa.gov/multimedia/images/raw/casJPGFullS23/W00017855.jpg
http://saturn.jpl.nasa.gov/multimedia/images/raw/casJPGFullS23/W00018011.jpg
Nice catch:
http://space.jpl.nasa.gov/cgi-bin/wspace?tbody=399&vbody=-82&month=9&day=15&year=2006&hour=15&minute=15&fovmul=1&rfov=20&bfov=30&porbs=1&showsc=1
Here is probably the best shot of the new "H-ring":
The H ring seems much darker and less reflective than the E ring, even (or maybe especially) in this lighting. I'd think this would argue against it being a pure-ice ring. Perhaps it is formed of icy/rocky debris from impacts on Janus and Epimetheus? I guess my first impression is that it's more of a dust ring that an ice ring.
-the other Doug
Handful of new images posted.
This is an odd image of the E-ring. The glow above it reminds me of an aurora. Is it something associated with the spokes or just an odd internal reflection?
http://saturn.jpl.nasa.gov/multimedia/images/raw/casJPGFullS23/W00018094.jpg
http://saturn.jpl.nasa.gov/multimedia/images/raw/casJPGFullS23/W00018092.jpg
It appears to shift between these two
http://saturn.jpl.nasa.gov/multimedia/images/raw/casJPGFullS23/W00018096.jpg
http://saturn.jpl.nasa.gov/multimedia/images/raw/casJPGFullS23/W00018097.jpg
Alan, I suspect is a reflection/diffusion effect from strongly illuminated main rings; this because is visible also in the"best view of H ring" http://www.unmannedspaceflight.com/index.php?act=Attach&type=post&id=7498 posted before where it's nature is clear...
dvandorn said "The H ring seems much darker and less reflective than the E ring" - isn't it much more likely that it's just optically thinner?
Phil
Cassini's Solar Eclipse labeled (91 KB):
http://static.flickr.com/82/247466918_474c7ee13d_b.jpg
I can see my house from here (or at least my home planet)! very VERY nice!
News Release: 2006-110 September 19, 2006
Scientists Discover New Ring and Other Features at Saturn
Saturn sports a new ring in an image taken by NASA's Cassini spacecraft on Sunday, Sept. 17, during a one-of-a-kind observation.
Other spectacular sights captured by Cassini's cameras include wispy fingers of icy material stretching out tens of thousands of kilometers from the active moon, Enceladus, and a cameo color appearance by planet Earth.
The images were obtained during the longest solar occultation of Cassini's four-year mission. During a solar occultation, the sun passes directly behind Saturn, and Cassini lies in the shadow of Saturn while the rings are brilliantly backlit. Usually, an occultation lasts only about an hour, but this time it was a 12-hour marathon.
Sunday's occultation allowed Cassini to map the presence of microscopic particles that are not normally visible across the ring system. As a result, Cassini saw the entire inner Saturnian system in a new light.
The new ring is a tenuous feature, visible outside the brighter main rings of Saturn and inside the G and E rings, and coincides with the orbits of Saturn's moons Janus and Epimetheus. Scientists expected that meteoroid impacts on Janus and Epimetheus might kick particles off the moons' surfaces and inject them into Saturn orbit, but they were surprised that a well-defined ring structure exists at this location.
Saturn's extensive, diffuse E ring, the outermost ring, had previously been imaged one small section at a time. The 12-hour marathon enabled scientists to see the entire structure in one view. The moon Enceladus is seen sweeping through the E ring, extending wispy, fingerlike projections into the ring. These very likely consist of tiny ice particles being ejected from Enceladus' south polar geysers, and entering the E-ring.
"Both the new ring and the unexpected structures in the E ring should provide us with important insights into how moons can both release small particles and sculpt their local environments," said Matt Hedman, a research associate working with team member Joseph Burns, an expert in diffuse rings, at Cornell University in Ithaca, N.Y.
In the latest observations, scientists once again see the bright ghost-like spokes -- transient, dusty, radial structures -- streaking across the middle of Saturn's main rings.
Capping off the new batch of observations, Cassini cast its powerful eyes in our direction and captured Earth, a pale blue orb, and a faint suggestion of our moon. Not since NASA's Voyager 1 spacecraft saw Earth as a pale blue dot from beyond the orbit of Neptune has Earth been imaged in color from the outer solar system.
"Nothing has greater power to alter our perspective of ourselves and our place in the cosmos than these images of Earth we collect from faraway places like Saturn," said Carolyn Porco, Cassini imaging team leader at the Space Science Institute, Boulder, Colo. Porco was one of the Voyager imaging scientists involved in taking the Voyager `Pale Blue Dot' image. "In the end, the ever-widening view of our own little planet against the immensity of space is perhaps the greatest legacy of all our interplanetary travels."
In the coming weeks, several science teams will analyze data collected by Cassini's other instruments during this rare occultation event. The data will help scientists better understand the relationship between the rings and moons, and will give mission planners a clearer picture of ring hazards to avoid during future ring crossings.
This forum digests new data so fast that by the time the press release shows up its already moved on to the next adventure.
Thanks Ian!
As Phil has pointed out, the H ring must have a very low optical depth. If you take a close look at Ian's above diagram (the one that shows the "panoramic view" with a longer-exposed inset) you can see that the H Ring is barely visible outside of the inset. The other rings are all clearly visible, though -- including parts of the D Ring that contain hardly any material at all.
Now comes the really fun part: figuring out what kind of orbit a particle in the H Ring follows. One possibility would be horseshoe orbits -- but, if that were true, the angular amplitude of the horsehoe of an H-Ring particle would have to be time-dependent, to accomodate the motions of Janus and Epimetheus within their mutual horseshoe! Since Janus and Epimetheus can approach each other to within about 5.5 degrees, I'm guessing any such "nested horseshoe" orbit for an H-Ring particle would be unstsable. Anyways, a fun project for someone in orbital dynamics.
Image of the Day: Pale Blue Orb
Earth is captured in a natural color portrait made possible by the passing of
Saturn directly in front of the sun from Cassini's point of view.
http://www.space.com/imageoftheday/image_of_day_060920.html
An image of Earth next to the rings and our Pale Blue Dot up close in inset:
http://www.nasa.gov/mission_pages/cassini/multimedia/pia08324.html?msource=ecard092006&tr=y&auid=1993417
http://ciclops.org/index.php regarding recent Saturn Eclipse observations. http://ciclops.org/view_event.php?id=55 look stunning, I can't wait to see the final http://www.luminous-landscape.com/tutorials/hdr.shtml of the images taken, if the rest of 'Saturn in Eclipse' looks as wonderful as the bit visible in the http://ciclops.org/view.php?id=2235 image it will be spectacular.
Anyone have any further composits they want to share? Or will we have to wait for the PDS release in order to see an improvement on what has already been posted?
There are lots more images on the RAW pages now, incluiding this amazing view of Enceladus:
http://saturn.jpl.nasa.gov/multimedia/images/raw/raw-images-details.cfm?feiImageID=83494
http://saturn.jpl.nasa.gov/multimedia/images/raw/raw-images-details.cfm?feiImageID=83579
Interesting sequence of G-ring images from the 19th. You can see the the material piling up on the inside of the ring. Which moon is going past as this is going on?
http://saturn.jpl.nasa.gov/multimedia/images/raw/raw-images-list.cfm?StartRow=65&cacheQ=1&browseLatest=0&storedQ=1321202
Is this yet another new ring, or merely just a clump in the E ring?
According to this Planetary Society http://www.planetary.org/explore/topics/saturn/moons.html the E-ring extends nearly to the G-ring, so technically it is in the E-ring as are the moons Methone and Pallene. Judging from the distance between it and the G and E rings I'd say it is near Pallene's distance. Since Janus and Epimetheus have a ring it makes sense that the smaller moons would too. IIRC the various parts of Jupiter's ring were traced to its small inner moons .
Anyone have any further composits they want to share? Or will we have to wait for the PDS release in order to see an improvement on what has already been posted?
This is a preliminary version of how I think the colors might look:
http://www.donaldedavis.com/2003NEW/NEWSTUFF/CASSECLIPSE.jpg
I used IR frames for red, clear filtered images (with the IR placed over it at about 30 percent opacity in 'multiply' mode to remove some of the long end of the spectrum) for green, and violet for blue. This was used mostly for the rim lighting around the planet, whose colour variations may be real but of highly uncertain actual colors. The white part of the sunlit atmosphere is overexposed and visually may well show colors similar to what the Apollo 12 crew were treated to on their way home as the Sun went behind the distant Earth. The backlit rings are patched together from different grayscale exposures and with some hand painting.
Don
Very very nice Don. Thanks.
There is an oppourtunity for an opposing view to be imaged as a companian to this set.
Although not identical, it still might be useful for comparison.
I have made a new version of the Saturn Eclipse view, based on an RGB series obtained with darker exposures well suited to bring out the colors of the dimmer limb glow along the north. This has been combined with hand retouching on the rings to bring out the subtle colors seen in other views along with some attempt at plausable overall brightness values. I especially tried to bring out the colors apparantly shown along the northern atmosphere in the RGB images.
The actual data will probably show more gradations in tone along the limb allowing better such color renditions to be made. Although looking at the preview jpegs is obviously a poor basis for judgement, I think it probable based on observations of Earth in similar lighting conditions that the brighter part of the atmospheric glow would appear blue along its upper fringe, and red as the atmosphere filters out the lowermost glow nearest the planet. What colors would visually dominate are problematical, but the overall thickness of the brighter portions of the atmospheric glow seem roughly similar in all 3 filtered images giving a very rough impression that no one color heavily dominates near the Sun. The bleed on the red channel far outshines that of the others, giving the bias for the color of the Sun. The optical reflections seen in some images has been added to make the Sun look like a bright red point source. A version without the reflection also exists.
Don
http://www.donaldedavis.com/2003NEW/NEWSTUFF/CASSECLIPSE.jpg
Very nice, Don! The red sun reminds me of those laser pointing thingies, sort of cool in its own way. I think you have Saturn upside down, though -- the north pole is at the bottom in your image. Which may explain the bluish tint of the atmosphere there. The rings might also be more bluish in forward-scattered light than that. See this VIMS sliced view of the unlit side:
[quote name='ugordan' date='Oct 3 2006, 09:24 AM' post='71098']
Very nice, Don! The red sun reminds me of those laser pointing thingies, sort of cool in its own way. I think you have Saturn upside down, though -- the north pole is at the bottom in your image. Which may explain the bluish tint of the atmosphere there.
Thanks! I have 'righted' it.
The rings might also be more bluish in forward-scattered light than that. See this VIMS sliced view of the unlit side:
This is intriguing. I wonder if any VIMS data was gathered of the limb glow during the eclipse?
Don
The occultation lasted about 12 hours and they more than likely acquired several VIMS data cubes during that period. The problem is the cubes have a pretty low spatial resolution and they're bound to be very pixelated. The color of the atmospheric glow will be deducible from the data, however. That is, unless the cubes get severely overexposed which is always a realistic chance.
zOMG
This is also discussed at http://www.unmannedspaceflight.com/index.php?s=&showtopic=3336&view=findpost&p=72285
image quote not needed and removed.
That is one of the finest images in the history of spaceflight. Period.
Here history is made.
A different way of seeing the rings as never before: visible all the way around without being obstructed by Saturn (simulation only now, images later)
http://space.jpl.nasa.gov/cgi-bin/wspace?tbody=699&vbody=-82&month=10&day=27&year=2006&hour=17&minute=00&rfov=2&fovmul=-1&bfov=30&porbs=1&showsc=1
http://space.jpl.nasa.gov/cgi-bin/wspace?tbody=699&vbody=-82&month=10&day=28&year=2006&hour=17&minute=00&rfov=2&fovmul=-1&bfov=30&porbs=1&showsc=1
Cassini already had a similar viewpoint 16 days ago. This is when we got images of the http://www.unmannedspaceflight.com/index.php?s=&showtopic=2954&view=findpost&p=72459.
I doubt Cassini will capture an all-encompassing mosaic here because:
1. The angular size of the ring system is huge, around 40 and 30 degrees, respectively. This makes it too wide even for the wide-angle camera which has a 3.5 degree FOV.
2. Cassini is near periapsis and a prolonged imaging sequence (such as this one would have to be) would take the s/c quite far and the imagery would be distorted, requiring fancy reprojections.
We'll probably get south pole images again, though.
While we are too close for preforming a full-system mosaic, that would be a great geometry to preform some radial and/or azimuthal scans
...wow. I am absolutely astonished by the amount of detail in this shot...the ringlets have ringlets have ringlets....
http://saturn.jpl.nasa.gov/multimedia/images/raw/casJPGFullS25/N00069999.jpg
This sequence has wide-angle frames looking scaled the way narrow-angle ones usually do.
Any idea what distance this was taken from?
Check out the star trails in http://saturn.jpl.nasa.gov/multimedia/images/raw/raw-images-details.cfm?feiImageID=88832 -- this is a testament to the precision of Cassini's relative tracking. A frame taken around periapsis when both the rings and Cassini are speeding like crazy, yet the image doesn't seem blurred the slightest bit! Furthermore, this was probably a short exposure, the star trails being long implies pretty fast tracking.
http://saturn.jpl.nasa.gov/multimedia/images/raw/raw-images-details.cfm?feiImageID=94157
Interesting view of the F Ring with two Moons either side.
Possibly three moons...isn't the Keeler gap satellite also visible at about 8 o'clock with respect to the image center (can't recall its name)?
Those sure don't look like Prometheus and Pandora, even if one takes into account they'd probably be thin crescents at this phase. These dots look way too small, my guess is cosmic ray hits. As for the third dot being Daphnis, I'd be more inclined to think that if we'd see waves on the ring edges. This also looks like ordinary camera noise conveniently placed in the Keeler gap.
Emily has a very interesting http://www.planetary.org/blog/article/00000811/ today, which refers to http://www.agu.org/pubs/crossref/2006/2006GL028146.shtml published in Geophysical Research Letters back in November.
EDIT: News@nature.com also had a http://www.nature.com/news/2006/061120/full/061120-14.html on this.
New high-res ring images down. This one is particularly interesting; there's an apparent spoke area about midway left & down of center, plus some pronounced kinks in some of the subrings...finally some subscale moonlet evidence?
http://saturn.jpl.nasa.gov/multimedia/images/raw/casJPGFullS27/N00075523.jpg
Be careful with that image. It's part of a dozen-frame ring scan and several frames got very stretched due to low contrast. Comparing this frame to neighbouring ones, this one was also severely stretched, in reality the contrast is nowhere as high as you can be led to believe. As a consequence that dust ring on the right is pronouncedly visible and also a light splat (which you identified as a spoke) that can also be visible in Titan raw images at about the same location. Usually, when you can see that dust ring very clearly it implies heavy histogram stretching and then flatfield effects and noise comes into play.
EDIT: On second look, nevermind that, I see this is a different sequence and the brighter splotch actually moves in subsequent frames. That's most likely a spoke, nprev. Good catch!
You're right, UG, and thanks for the reality check...raw imagery has its bear-traps for the unwary! Looks like I got lucky, is all...
Meanwhile, here's an interesting example of http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=2463 in the F-ring. What's really fascinating here (at least to me) is the possibility that rather than being disassociated this material might actually be in the process of being accreted into a discrete object...the causal arrow, if you will, is not obvious (although entropy does argue for dissolution). Still, seems like there might be a lot of lessons to be learned with respect to things like planet formation here.
I've been messing around with the Sep 15, 2006 backlit sequence from the PDS. While there are numerous wide-angle frames that are taken at half resolution, there's only one RGB set taken at full 1024x1024 resolution and that's of Saturn itself:
http://farm2.static.flickr.com/1118/1116325066_c9867e35b2_o.jpg.
Vertical charge bleed in the red channel was so big I had to cheat a bit to remove it and make it less ugly.
Also, since the CICLOPS http://ciclops.org/view.php?id=2230 image advisory states the color was generated from UV, clear and IR frames (there are no complete mosaic coverage RGB sets available, only the left ring ansa region and it's pretty overexposed), here's what actual RGB color gives, these were taken with 2x binning, it's a quick 4 footprint mosaic (incomplete, there's a bit of additional E ring coverage available I omitted):
http://m1.freeshare.us/view/?167fs325180.jpg
The bright dot is, of course, Earth.
Finally, a colorized composite of 2 clear filter NAC shots of Enceladus, the upper one is a 1.2 second exposure, the lower one is a 18 second exposure. Views on the right are enhanced to bring out subtle plume structure. The overall hue is that of the E ring seen at this phase angle (178 degrees).
http://farm2.static.flickr.com/1027/1117153034_4c62a793bb_o.png
Note Enceladus' shadow on the E ring in the lower composite.
EDIT: And here's a merge of the two exposures in an attempt to maximize S/N ratio, again with (too?) heavy enhancing done:
This orbit they have really concentrated on Saturn images. I guess because of the phase angle, and the leisurely pace of this larger than most orbit, has made it ideal to just look back and watch the Saturn weather.
leisure pace? surely you jest. The Cassini navigators are always in a state of near panick when on-shift, neurotic when not. Think about level ten Tetres.
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