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/...mp;auid=1993417

CICLOPS post regarding recent Saturn Eclipse observations. The pics released look stunning, I can't wait to see the final HDR composit of the images taken, if the rest of 'Saturn in Eclipse' looks as wonderful as the bit visible in the pale blue orb 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/imag...eiImageID=83494

http://saturn.jpl.nasa.gov/multimedia/imag...eiImageID=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/imag...storedQ=1321202

Is this yet another new ring, or merely just a clump in the E ring?

Click to view attachment

According to this Planetary Society webpage 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

yowza, that is really rather good.

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.p...ost&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?t...=1&showsc=1
http://space.jpl.nasa.gov/cgi-bin/wspace?t...=1&showsc=1

Cassini already had a similar viewpoint 16 days ago. This is when we got images of the south pole.
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/imag...5/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 this image -- 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.

Yes, absolutely.
Looking to the full sequence, it seems Cassini mapped all rings... I made a stitch of the first five pictures showing A and outher B and structure is breathtaking :
Click to view attachment
(I had to heavly correct gamma/contrast/luminosity in order to match images, followed by 90-deg rotation + vertical blur in order to reduce noise).

Interesting also this picture: I do not know if the glow in the space between A and F rings is a optics reflection, but if is real (tenuous material between illuminated from behind) the small dark object in the center could be Prometheus...?

http://saturn.jpl.nasa.gov/multimedia/imag...eiImageID=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 blog entry today, which refers to Jones et al. [2006] published in Geophysical Research Letters back in November.

EDIT: News@nature.com also had a story on this.

This is a movie of 26 frames centered on this one:
Click to view attachment
Prometheus is barely visible in the first frame (N00073840):
Click to view attachment

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/imag...7/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 dynamic activity 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:
.
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 backlit mosaic 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):

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).

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:
Click to view attachment
The two most prominent jets trace back to the south pole nicely, but there's a peculiar detached, slightly curved 'puff' or two to the left of the long jet that doesn't seem to trace back. It appears torn apart. Even more curious is another streak that appears to emanate above the northern latitudes. I don't think either is an artifact of the processing (similar to the brightening around shadow edge and the limb).

Is Enceladus' gravity strong enough to perturb the jets that hard?

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.

Hi - were those ray like features near the bottom pointing away from Saturn a camera reflection or some type of new phenomenon? I recall seeing more of these in other versions at other azimuths as well.