Looking at the 500 most recent raw images from Cassini, one of the pages was filled with nothing but images of the rings at various angles and locations. The tiling of these images on one page was unintentionally interesting and I thought we would repeat a more intentional version here with those same images.

This image taken on January 18, 2008 from 988,018 km, reminds one of some of those vintage Voyager images of Saturn (seen at left) from back in the early and mid 1980’s. Just compare at the incredible differences between the quality and color of the Voyager vs. Cassini images. Saturn images during the Voyager era were all consistently yellow and brown, but today’s Cassini images reveal Saturn to be a rich peach color mixed with hints of yellow and brown. We also have the advantage of being witness to the rich blues currently appearing in the northern hemisphere which did not exist in 1981 or 1986.

Prometheus disturbing the F-Ring as it passes. We have seen this animated before, but perhaps not from such a vantage point.

The one Saturn image that we keep coming back to at wanderingspace seems to be the Ian Regan portrait of Saturn. The composition, angle and color captured in the shot somehow seem to be better than any other. While there are a few other full Saturn images now available from the Cassini mission, none seem to have captured the drama that this one does. The angle that the ring shadows fall on Saturn’s disc, the phase that Saturn happened to be in at the time and the color available as the shot was taken from a more northern position. However, trying to apply the image to larger scale resolutions was not possible as the resolution in the orignal would require that the rings be extended to fill the frame on the left, right, bottom and potentially the top as well (I was also curious to see if the image was just as impressive if it was not angled and cropped as it is in the original). Extending the rings in one direction is easy enough, but doing it on all sides is near impossible to try to do in any image editing software such as Photoshop.

Instead, a one pixel wide swash of the rings was sampled and turned into vectors using Adobe Illustrator. This further allows Illustrator to stretch and curve the ring information captured without having to worry about resolution or pixel distortion. The row of rings was then applied to a brush pattern and applied and wrapped to a simple circle shape. Now the rings are in full circle and the proportions are adjusted. That full set of rings was then rendered in 3-D software and the correct angle as well as perspective was applied and matched with the original Ian Regan image underneath the render for reference.

After that, all that is left to do is merge the Regan image to the rings (and maintain as much of the original image as possible) and artificially add the disc shadow that would fall upon the rings behind the planet iteself.

To see the image in hi-res use check out the 2560×1600 wallpaper sets for The Planets and Saturn Scenes

There have been some nice NASA animations of the interaction between some “shepard” moons and the rings, but this has to be the most impressive. There are some blank frames in there for gaps in the data… but the effect is still easy to follow.

Among the various worlds in our celestial neighborhood, Saturn stands apart as a most photogenic. With the help of a complex system of rings it naturally lends itself to more scenic images as compared to the more detail oriented images we see from such other places such as Mars or Jupiter. The “Saturn Scenes” set (downloadable here as a zipped file) was compiled from some of the best scenic images from the Cassini mission that had the potential to fill a 2560×1600 frame.

In order to completely fill that frame out some rendering and sampling has been applied to the original images. These additions are briefly noted in the images themselves and are as noted here…

DIONE AND SATURN features the moon Dione passing in front of the edge of Saturn’s disc. The original image would only fill about 1/4 of the frame so some of the details have been sampled and expanded to fill out that full frame’s proportions. The details of the rings are sampled from this image and based upon other photographic references. The left 2/3 of the rings seen here were rendered and are not actual. The lower 1/5 of Saturn’s disc was sampled and extended from the original image. Lastly, the top darkest ring shadows were rendered based upon a fair amount of actual data that was actually present in the original but was cropped short.

SATURN (which is named “SATURN-2.jpg” in the file name) has had a considerable amount of rendering to extend the details of the rings to fill out this larger 2560×1600 frame. The original color composite work was masterfully performed by Ian Regan for unmannedspaceflight.com and has become a wanderingspace favorite. In order to extend the rings to fill out the frame as accurately as possible, a one pixel wide sampling of the full set of rings was captured and digitally translated to vectors. These vectors were then stretched and applied to a circle path which was then rendered in 3-D software to achieve the correct perspective of the original. Once a match was made, the new vector based rings were then blended into the actual original image and some masking was applied to represent Saturn’s shadow falling upon the rings. Despite the heavily rendered nature of the rings, virtually no part of the disc of Saturn itself has been altered and is 99.5% original and actual.

All other images are actual and unaltered.

NASA released an unusually large amount of color images to the Cassini website recently. Most of what is shown here on this site are actually images put together by freelance imagers who access the raw files and do some stitching together of filtered images. Color images coming straight off the Cassini website are a rare event, so when about 8 appeared in the gallery a few days ago… it was an unexpected gift.

Saturn as seen from the unlit side of the rings.

A family portrait of the Saturn System. Moons visible in this image (you need to click the preview) are Dione at far left, Enceladus near the left side ring edge, Mimas a speck on ring shadows on the western limb, Rhea against the northern hemisphere, Tethys near the right ring edge, and Titan near lower right.

Titan and a small moonlet named Epimetheus share the frame with Saturn’s rings.

A rare color view of both Saturn and Titan in one frame. This is the only one of its kind thus far in the mission.

A small rainbow appears as sunlight streams through Saturn’s rings.

Hopefully by now, most people are aware of the shocking activity at this small moon named Enceladus at Saturn. It appears the moon is continually spewing out material (likely water-ice and rock) from a number of geysers located around its southern pole (see Life in the Hood: Enceladus for reference).

This image was taken around September of 2006, and reveals how Enceladus is actually constructing another ring around Saturn. The “ring” is not normally very visible, but by taking the image with the sun almost directly behind the structure - the particles become back-lit and appear brighter, like dust in a ray of light.

Close inspection of the image reveals quite a bit going on in there. You can see a darker path behind Enceladus as it sweeps up materials already left in it’s path from previous orbits. While in front and around the small moon, you can see jets of material being generated and going into orbit around Saturn. A similar phenomenon is happening at Jupiter with the torus created by Io’s volcanos as well, but I am unaware of any images illustrating that phenomenon as detailed as the one seen here.

Not much to say about this one but, wow. This is better than the famous hi-res Saturn image from early in the Cassini mission. The composite image was made by Ian Regan who is a freelance imager.

Gordan Ugarkovic has a great collection of reworked Cassini images on Flickr. I contacted Gordan about showing some of his images here on wanderingspace and he was ever so gracious. As many people Gordan is “somewhat underwhelmed by the frequency the Cassini Imaging Team releases color composites”, so it is up to excellent freelancers like him to compile this information from the data files which are made public by NASA. Problem is that these images rarely make it to the mass media and we are stuck with the dozen or so color images the NASA imaging teams decide to produce in a year.

WALLPAPER NOTE: The left 1/3 of the “Three Moons” image was extended in Photoshop using data at the edges of the original image which was cropped to a square format. This “fake” imagery was only applied to that area of the rings and the rest of the image including the moons is actual.

Here are some other images from Gordan which are some of my favorites, but don’t trust my editing… go to the gallery and have a look yourself. For the sake of posterity I have added a permanent link to his gallery on the right side of this blog where you may note that there are already a few others linked. There were two additional ones but the sites have been taken down since I linked to them?! Hopefully the three left will stick around for a while and I will in time add more to the collection.

Tethys and Saturn’s Hazy Limb

Mimas and Prometheus on Rings

Io on Jupiters Edge

Currently the Cassini spacecraft is orbiting Saturn during Saturnian Winter unlike when Voyager sped by in the 80’s when it saw an almost globally peach colored Saturn. During this winter, the rings tend to keep the region in shadows and the theory goes that this lowers the temperatures and break up the peach colored clouds and “clear” the skies to reveal this blue. If this is the case, we are seeing deeper into the atmosphere here than we do in the areas blanketed by the more peach colored top clouds.

The image shows the northern pole of Saturn and those bands are the shadows of the rings on the cloud tops. You can see some smaller cloud formations in between the shadow gaps which gives a very alien Saturn some Earth-like familiarity.

One of my favorite wallpaper images from the Cassini mission. This image almost looks like one of the fantastic Chesley Bonestell images from the 80’s only its not a painting. What you see are Saturn’s rings along the bottom and tiny Mimas floating across Saturnian cloudtops which are being shadowed by the rings. It is thought that these deep shadows, in addition to Saturn currently being in winter, somehow cause less clouds to form in Saturn’s northern hemisphere and create the blueish appearance seen here. When the Voyager’s passed by Saturn in the 80’s the entire globe appeared to be peach colored and lacked any of the blues you see today.

IMAGE NOTE: The left 1/5 of the image (the rings) is a digital extension of the image data found near the edge of the original image. This was done simply to fill out the proportion as the original was cropped to about 4/5 the the width.

This image of Saturn is making the covers of many “Year in Science” issues out there right now. It may not have much science in it, but it sure is just about the most visually engaging image of the year. Hard to think that this IS NOT A FALSE COLOR image. Although it would be my guess its just a bit over-exposed… but then again so are most your holiday pictures.

In one of Cassini’s more surreal images, the small moon Mimas is seen floating across the ring shadows cast upon Saturn’s cloud-tops. Mimas is a rocky 400km moon whose most notable feature is a 130km crater that dominates its appearance.

IMAGE NOTE: The original image was close to a square cropping, so a large part of the 1/3 left of the image (which is mostly black space) has been extended using data from the rest of the image to duplicate details and fill out the dimensions. The rest is the real deal.