Jan 5 2009, 11:08 PM
Beautiful work. The ring shadows are getting really narrow and the now faintly bluish color in the northern hemisphere will soon be completely gone.
Jan 5 2009, 11:26 PM
Yes, the northern hemisphere is really displaying a varied selection of pale blues and greens at the moment. Also, it won't be long before the south pole completely disappears into the darkness of winter:Click to view attachment
Jan 11 2009, 07:48 AM
Here's another two-frame mosaic:Click to view attachment
Jan 11 2009, 03:16 PM
I couldn't resist doing this mosaic either; there's some rather picturesque storms in the southern hemisphere:Click to view attachment
Jan 13 2009, 11:17 AM
This view from the south has the C-ring visible in silhouette, and a moon shadow (although I don't know of which moon):Click to view attachmentEdit:
Looks like the mystery moon is Tethys
Jan 13 2009, 01:18 PM
Again, good stuff, Ian! These will be great once the data hits PDS. I might as well show a mosaic done in a similar vein, showing the long-lived storm captured on March 4, 2008 in calibrated color:
It's been sharpened a bit to enhance cloud features and rotated so north is roughly up.
Jan 16 2009, 04:48 PM
Wow, a nice one from the raws:
Jan 16 2009, 09:28 PM
I try not to post when I've nothing more to contribute than "wow!"; I'll make an exception in this case. That is stunning - like a minimalist companion to the classic Eagle Nebula HST image.
Jan 17 2009, 02:25 AM
That's a wonderful mosaic Gordan - what method did you use to sharpen the image? It's worth comparing to this excellent amateur image that was taken at around the same time:http://www.flickr.com/photos/ethanallens/3138962663/
I must learn how to calibrate the PDS imagery one day... at the moment, I just enjoy the 'hot off the press' feeling of putting together a colour view from the raws that were taken only a couple of days previously.
Jan 17 2009, 03:38 AM
QUOTE (imipak @ Jan 16 2009, 01:28 PM)
I try not to post when I've nothing more to contribute than "wow!"
Ditto, as I push jaw back in place.
The moon (Prometheus?) and shadow give a 3-D quality. It is beautiful, eerie, and seemingly unreal. It brings the feeling I got watching the last part of 2001 A Space Odyssey years ago.
Jan 17 2009, 04:02 AM
That's one of the few pictures you see that make you realize that you really are
living in the 21st Century, seeing sights only dreamed of before, flying cars be damned! Stunning beauty that touches the soul, is all.
Jan 17 2009, 11:15 AM
Ian, I use a basic unsharp filter when trying to enhance small scale features such as clouds. Usually I set the filter radius between 3-5 pixels.
As for calibration, it's not rocket science - Bjorn's IMG2PNG tool can do that for you. All you need is the calibration DVD volume, some 600 megabytes IIRC.
Jan 21 2009, 05:26 PM
Here's a little preview of one side of a full-globe mosaic that's on the RAW page at the moment:Click to view attachment
Jan 27 2009, 02:50 AM
Well, I finally finished the full-globe mosaic - I'm not 100% happy with it, but I suppose there's only so much you can do with the raw JPEGs. Hopefully, this has more realistic colour than my previous efforts:Click to view attachment
Jan 27 2009, 03:05 AM
Jan 27 2009, 09:22 AM
Great stuff, Ian! Very realistic colors, I think.
Is that Rhea in the shot?
Jan 27 2009, 06:13 PM
Nice work, Ian; straight to the blog!
Jan 29 2009, 02:56 PM
Thanks for the great feedback guys! I'm just happy that the colour balance seems to be about right this time. For comparison, here is a reduced version of the raw composite:Click to view attachment
The adjustments I made at this point, for what it's worth, were as follows:
- R/G/B levels: -6 -16 -35
- and Gamma correction: 0.70
Feb 1 2009, 12:26 PM
What a pity this shot of Prometheus's shadow on the rings is truncated:http://saturn.jpl.nasa.gov/photos/raw/rawi...?imageID=181348
Feb 1 2009, 04:06 PM
That's Epimetheus's shadow actually
Mar 23 2009, 04:30 PM
Apr 20 2009, 06:24 PM
You want "exquisite"? Look no further than The Boston Globe's "Big Picture" special on Cassini...http://www.boston.com/bigpicture/2009/04/c...ed_mission.html
Apr 20 2009, 10:43 PM
Great find, Stu, and terrific to see Cassini featured so well in a 'popular' venue!
Apr 20 2009, 10:54 PM
I know the guy who runs the Big Picture, Alan Taylor. He's as into space exploration as everyone else here. He filters through the raw imagery on several missions pretty regularly. (I keep trying to get him to come on by. I think he'd like the place.)
He's done a few other Cassini summaries over the years, like this one
on Flickr, and others on the Big Picture.
He's the same guy who did the "All (known) Bodies in the Solar System Larger than 200 Miles in Diameter
Apr 21 2009, 09:57 PM
QUOTE (maschnitz @ Apr 20 2009, 11:54 PM)
I think he'd like the place.
Judging by that selection of Cassini images, I'm sure the feeling would be mutual.
May 22 2009, 03:51 AM
May 22 2009, 12:15 PM
What is that? The gravity of a shepherd moonlet causing a ripple in the rings?
May 22 2009, 01:32 PM
Very interesting. What did cause that.
May 22 2009, 01:50 PM
May 22 2009, 03:18 PM
The orbit of Prometheus is excentric, so it gets closer and furether away from the F-Ring. I undrstand the F-Ring is also a little excentric itself. The amount Prometheus dives into the F-Ring and how deep of a gore it makes depends upon how the two excentricities line up. I belive they will maximally interact some time in August. The movie was obviously made targeting Prometheus--so you have a moving frame of reference. The blank/black part of the movie was when Prometheus was in Saturn's shadow.
Jun 21 2009, 06:26 PM
Here is a nice image. Note how the rings at the bottom of the image are lit by Saturn, then fade to illumination from the Sun. Some of the rings change from light to dark and other dark to light. As a plus, we even get a moon shadow. Carolyn, special request: Take a set of color images next time--even better, take a color mosaic with the NAC. Click to view attachment
Jun 29 2009, 10:35 AM
I've gone back to the Cassini solar eclipse sequence of Sep 15th, 2006 and did a couple of color shots I haven't seen reproduced elsewhere. First off, for context, is a wide-angle, full resolution RGB shot of Saturn that I posted already, but I've since cleaned up and sanitized the charge bleed flare a bit:
If you click on the above image, you'll be taken to the description page and then if you hover your mouse over the image several inset boxes will appear. Clicking on the text below them will bring you to a narrow-angle color zoom of the limb location. Click "all sizes" to see the wide-angle frame in full resolution. It's twice the resolution of the disc in the official eclipse mosaic
and uses actual RGB data, while the official mosaic is based on infrared and UV data. Compare the respective colors each approach gives.
Here are direct links to the limb shots (the ones that weren't overexposed badly):
They aren't much to look at, but as I said - we don't often get to see Saturn's sunsets like this. The sky around the north pole is a noticeably clearer blue color.
Particularly interesting to me is the rightmost one here where a nicely defined, detached haze layer can be seen running around a narrow band across the planet's equator (the terminator itself is overexposed white and has two charge bleeds I attempted to clean up so don't over-analyze any kinks/structure in it). I've seen the haze layer before in some shots
, but not in others and this I guess explains why.
If you look at the first two images in a dark environment, you can get a hint of the E ring beyond the planet. Brightness settings are individual for each footprint as I wanted maximum brightness without saturation so they are not cross-comparable.
Jun 29 2009, 12:34 PM
Absolutely stunning, Gordan; thanks!!!
Jun 29 2009, 02:54 PM
Excellent work on the images, thank you.
Jul 19 2009, 01:03 PM
Wow, those rings are really
getting dark...Click to view attachment
EDIT: rotated image back so north is up
Jul 19 2009, 07:47 PM
That photo is beautiful... the framing/cropping is perfect. I know a photo's dramatic when I start humming Also sprach Zarathustra.
Jul 19 2009, 11:16 PM
Not bad ugordan. keep in mind that we are looking over the north polar region at the time, the unlit side of the rings. So north was "up" in the original frames.
This image set certainly makes a great desktop background.
Jul 20 2009, 11:10 AM
That's the north hemisphere? Geez, look away for a few weeks and the blue color vanishes completely. Oh well... Though that would explain why the rings turned out darker than I expected.
Jul 20 2009, 04:41 PM
Yeah, the image was taken while we are above the ring plane.
The blue color is there to an extent. We can definitely see bluish haze over the NP region (actually, it more green, I guess that's what you get when you combine blue haze and yellow atmosphere). Fainter haze can be seen further south, but you are right, it isn't as distinct.
Jul 25 2009, 08:12 PM
Very nice images ugordan. It seems like the blue layer even at the NP is slightly detached, so it isn't simply Rayleigh scattering in a clear atmosphere making the blue as I would have anticipated seeing.
Jul 25 2009, 10:24 PM
That's an instrument artifact, Steve (talking about the image above, not the narrow-angle eclipse frames). Wide-angle blue frames are always more fuzzy than red/green, even when looking at solid objects. These shorter wavelength images also appear to me to have a slight geometric distortion (chromatic aberration?) and one would need to slightly resize them to register with other filters better. I didn't do that above, hence the blue fringe.
Aug 11 2009, 01:40 AM
Out of interest I remapped a timelapse sequence of Prometheus moving along the F ring so that it would reveal the gravitational effect over a longer distance.
Please note that the shape of the ring doesn't represent it's actual path. I hope you like it. Click to view attachment
Aug 11 2009, 02:40 PM
You did a beautiful work, phase4!
Aug 15 2009, 02:45 PM
Very very very hard working on the "raws" of the 12th july mosaic. A lot of shifting between frames because of the move of Cassini during the taken.
See the working space in Gimp :
And the final result :
There is aways shiftings and exposure adjustment is perfectible, but this is the best I can do now.
I think that Gordan will produce a better picture than mine
Aug 15 2009, 03:26 PM
that is very cool
Aug 15 2009, 05:18 PM
Perhaps it's perverse, but I find the small reminders of the nature of the source images adds to the impact of the finished product (as did seeing the work in progress.) Bravo, Ant!
Aug 15 2009, 05:29 PM
Nice work, Ant. It's hard to appreciate how difficult it is to stitch a mosaic like that from a moving observer if you've never attempted it.
QUOTE (Ant103 @ Aug 15 2009, 04:45 PM)
I think that Gordan will produce a better picture than mine.
Nope, I'm not even trying this one
As you saw, it's tough enough to fudge the perspective shift, let alone dealing with colors in uncalibrated data and trying to bring out *any* hint of rings consistently. This is as far as I'll go:Click to view attachment
Aug 16 2009, 08:55 AM
QUOTE (ugordan @ Aug 15 2009, 12:29 PM)
Nope, I'm not even trying this one
As you saw, it's tough enough to fudge the perspective shift, let alone dealing with colors in uncalibrated data and trying to bring out *any* hint of rings consistently. This is as far as I'll go:
Very nice image though. Why try to bring out the rings though? Isn't that what the Saturnian Equinox is about? No visible rings?
I never see Saturn without rings. Sure they're beautiful, but it's like wearing the same hat every day.
Aug 16 2009, 10:24 PM
Here's my first crack at a color Saturn near-equinox image (August 3rd image). Northern hemisphere is shown (rings in shadow):Click to view attachment
Aug 17 2009, 03:03 AM
Storms in the north pole of Saturn on August 12, 2009:Click to view attachment
LRGB image taking the luminosity from IR3 and the RED-GR1-BL1 channels. Lotsa contrast manipulation and high-pass filtering. Done for artistic effect, not color accuracy.
in the background.)
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