After hours of hard work (don't forget that this is my first ever attempt at producing a colour mosaic on this kind of scale), here is Saturn in all its glory!

http://img442.imageshack.us/my.php?image=s...ianregan6jl.jpg

There are still a few tweaks to be made, of course, and I hope to post the final version at the weekend.

Enjoy!

Ian.

Wow! Extremely impressive work!

Looks great! One 'error' I noticed though is that the rings are brighter at upper right than in the lower left half of the image. The rings should be noticeably brighter in the lower left half than elsewhere due to Saturnshine - maybe one of the tweaks left to do.

That is totally awesome! Great work, hard to believe that's your first!

I wish I had time to play with Cassini images, but I see there is no need anyway with all the great stuff being done by you lot

James

Awesome! I didn't think the footprints would align well but you made it look seamless! Great work!

cool!
in the top right, are those moving moonlets (a similar effect as the dust devils by Mars Express)?

Yep, looks like Prometheus and Pandora and either Janus or Epimetheus.

Bravissimo!

Too bad all I get is an Imageshack page with a link to host my own pictures, but no image...

-the other Doug

With his permission, I've featured Ian's work on the Riding with Robots site.

BRAVO Ian, on a magical job, it's a very inspiring view you provided

Nico

Ian, absolutely glorious !!!!

I'd like to use this for my Cassini talk at a Planetarium in 2 weeks (with credit to you, NASA etc), assuming thats OK.

Cant wait to see your latest and greatest

ken

Apparently, the raws page houses at least two nice global views from above. One is the one Emily mentioned in her blog and Ian superbly mosaicked, and the other is a higher phase view and looking down from a higher inclination. I ran across it on an Astronomy Blog, the author still seems to be working on it, but it promises to look equally impressive.

I can't wait till this stuff hits the PDS.

Ian's latest version is now on Emily's blog

http://www.planetary.org/blog/article/00000847/

I'd like to thank both Emily and Bill for kindly displaying the Saturn mosaic on the Planetary Society blog and the Riding With Robots website. It certainly makes all of the hours invested in the creation of the image worthwhile!

The wonderful repsonse from the UMSF stalwarts here is also greatly appreciated, and hopefully I will get around to implementing the suggestion that Bjorn made sometime soon. I am only an amateur at this game, with a minimal amount of knowlegde in the image processing field, so I welcome all constructive critiscism from the resident gurus and experts here.

I did see the second mosaic in the Cassini raw directory, but decided against putting that version together since I was so burnt-out from doing the first one. I'm pleased to see that someone else is putting the necessary time and effort needed to make sure that this Saturn portrait gets properly reproduced too.

Finally, Ken, of course you are welcome to use the composite in your lecture - thank you for being such a gentleman to ask permission in the first place. In general, I don't mind at all if people use my work without seeking my approval, but to go that one extra step is certainly a sign of pure class.

Good luck with the lecture!

Ian.

Here's a very quick-and-rough colour composite using some of the latest raw Cassini imagery:

Click to view attachment

Ian.

Great work Ian, one more time!

Wow, lots of weather going on there... vortices large and small. Very neat.

Stunning work Ian, many congratulations!

Like Ken I'd like to ask your permission to show your image to others. I'm giving talks in 4 different junior schools next week, and also speaking to two community groups, and I'd love to show them your pic. Is that ok?

Yes, of course Stu - go for it!

Here's another one for the album:

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One more for the road...

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I downloaded the frames for those in case I found the time to try to put them together -- but you beat me to it -- and did a much nicer job than I would have managed to! Keep it up!

Emily

Thanks Emily. I sure the colour balance isn't correct, and that Bjorn or ugordon could do a better job in that respect, but despite that, I'm quite pleased with the results so far.

My latest composite is a natural colour view of the south pole:

Click to view attachment

Cheers!

Ian.

Poetry in space.... Ian, Bravo again!

Edit: removed the quoted section and added a enhanced version (not realistic, only in order to highlight atmospheric features and chromatic differences):

Ian, these are just stunning, really...incredible. It's the next best thing to being there, which probably none of us will ever get to do, so thank you very much!

I think this must be my favourite view yet:

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Thanks nprev - I'm really flattered by your very kind words! I'm having a great deal of fun with the Cassini imagery at the moment, as you can no doubt see.

Ever since I first discovered this website, I have wondered and marvelled at the fantastic work done by the other members here - it's amazing to see so much talent in a single forum. It's very rewarding for me to finally be able to give a little bit back to the community that has provided me with so many truly great images over the past 18 months or so.

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Here's a short GIF animation showing Cassini approaching the ring plane from below. Note how several atmospheric features can be seen moving from West to East during the sequence:

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Zooming in on the northern hemisphere:

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Ian.

Enhanced southern-hemipshere movie (shown in reverse):

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More amazing stuff , thanks a lot Ian.

James

"Saturn in Widescreen"



http://img172.imageshack.us/my.php?image=saturn4kp9.gif

You're welcome James!

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Ian this is great work. For some reason people have been somewhat shy of processing the Saturn images. I am glad you have stepped up to the plate and really taken on this task. Keep up the good work.

EDIT: My wife who isn't all that interested in my UMSF hobby, just glanced over my shoulder and declared "Oh, now that's nice."

This is some fine work you're putting out Ian! The only comment I have is the output is a bit too blue-tinted. My goofing around with VIMS spectrometer data (check out the lower Saturn pic here, it's a similar viewpoint) to get more accurate colors basically suggests a "true color" appearance very similar to this CICLOPS view, though the saturation in that image might be a bit too high.

A new set of colour images, with some nice views of the shaded side of the rings:

Click to view attachment

I do plan to go back and adjust the colour balance of these images at some point, so thanks for the pointer Gordon. Unfortunately, the stretching that is applied to these raw JPEGs means that two views that should have identical contrast, hue and saturation, end up all over the place.

What do you suggest is the best way to correct the colour in these images? Should I manually adjust the brightness and contrast of the B&W raws, or should I simply change the Red/Green/Blue values of the resultant composite?

Cheers,

Ian.

When I do raw processing, I composite each footprint individually (aligning the 3 channels basically) and then paste them all into one image in Photoshop as different layers. Then comes the adjusting each footprint's color channel to match all others. Once they all match up (more or less), you can flatten the image and do brigthening/dimming of each channel to approximate the calibrated output. A calibrated output will have Saturn a dullish-yellow color, not fancy colors. You can then mix the three channels sensibly to produce a satisfactory result. Mixing will wash out saturation, but you can always increase that up later. Admittedly, it's a lot of work to work with raws and I personally kind of lost the interest to do it twice, first with raws and then do it the "proper" way once the data hits PDS.

BTW, that latest image is great! It's so Voyager-esque. In fact, you can use that moon that's visible to correct the colors a bit, make it turn white and you'll have colors closer to calibrated ones. Usually you can't rely on stuff like that, though. Did you use the violet or blue filter, this looks to me like it's violet?

Cassini spent so much time on the night side that I lost track of just how south ring shadows have actually moved.

I took the liberty of tweaking your image a bit, I hope you don't mind:

It's just way cool

I taken some liberty too; still not perfectly matched with Gordan reccomandation, but a little more realistic.
Click to view attachment
Thanks again, Ian.

Wow, great stuff!

Ian,

everything in your latest posts is exquisite. Well thank you for the OK and I'd may like to use a few more like the gif too. Gee I have to revise the entire Saturn portion of my talk set for Feb 14 in Philadelphia! forum members welcome
http://www.rittenhouseastronomicalsociety.org/meetings.htm

Suggestion: can you slow down the gif somewhat please? I think it will help the audience appreciate and understand more easily. thanks

ken

Jaw-dropping, amazing work, everyone! I've been waiting for these perspectives for years. One question for ugordan specifically regarding the natural color views: Looking at the difference between your processed images of Saturn and JPL's, the pronounced blue tones in the northern hemisphere seem much more muted in yours. I know next to nothing of the characteristics of the filters or the technical aspects of combining them, but what would we actually see If we were there? I've had many questions from friends about that unearthly (and once-unsaturnly) blue, as it gives the place an unfamiliar look to them. I'm inclined to guess your processing is more accurate, especially as you've cranked out hordes of wonderful color products that JPL seems averse to releasing. Anyways, congrats to Ian, yourself, and others in this thread. I will certainly have a difficult time kicking you off of my desktop.

Had to improvise a little bit with this one, as there seems to be a Red frame missing, somewhere:

Click to view attachment

Exploitcorporations, I can't really say my processing is all that more accurate than JPLs as there are a few things to consider here: The colors in my latest Saturn images in the gallery are based on my experiments with VIMS data and choosing channel mixes to resemble that as closely as possible. I've still to figure out the best mix, but I'm working toward it. If anything, the blue cranium might be a bit too subtle in some of my views. The other thing that might affect your perception is I have a lot of high phase Saturn composites there and I think the blue tones aren't in reality as pronounced in those views. I also tried to keep the saturation lower to match the softness of the VIMS views, especially when a proper 2.2 gamma is applied.

That said, I do believe CICLOPS went overboard with saturation on a few color composites, making other Saturn shots weirdly yellow and dull compared to those. For reference, here are two of my ISS views that closely resemble results using VIMS: Ring Shadows 1 and Saturn's North. Compare the second one with the Blue Cranium official release.

Just for a quick reference, here are some of VIMS results with a slightly lower gamma and compare the intensity of the colors there. Also, a VIMS mosaic of the blue cranium from a low phase angle.

If it is any consolation, ugordan, that's what I always get for my Saturns, a more grayish northern hemisphere than bluish.

A simple RGB composite will tend to give you that, but you'd need to mix the channels in a right ratio to compensate for the effect of different bandpasses and the fact green channel overlaps quite a bit with the other two. It comes down to sensibly "fudging" to match what the scene actually looks like. Worse, different targets often require different mixes -- Jupiter would turn out quite weird with the same mix as used on Saturn, even with the same filter sets. The "correct" mixes might even vary with phase angle, but I might be wrong on that one.
Really, you loose a bit of "true" color information by using only three color snapshots (opposed to full visible spectra) and that's why I give more weight to VIMS produced colors as they are more "scientific", taking into consideration human eye specifics. Especially since they pass reality checks such as white Enceladus and gray Mimas. Neglecting weird bluish Venus colors and a brownish Moon here.

But, yeah, I think some of you at CICLOPS might have gotten a bit carried away with a few composites.

Thanks ugordan for the insights. I missed your referenced VIMS post...very interesting stuff. I need to study up on gamma correction. As an aside, no offense intended toward CICLOPS, especially regarding the icy satellite mosaics. The only important colors there are the sickly green of envy (VP-that's your mosaic of Enceladus from the Feb. 2005 NT encounter? Mine still looked like a Hockney collage after two years of struggle!) and the cool auzere of the blue screen of death.

Waiting for another Ian stunning stitch, I played with the last pictures taken on Feb,6:
Click to view attachment Click to view attachment
First one is an RGB combination, the latter is a pseudo-color image based on MT3, green and B3 filters.

Oooh, very pretty indeed dilo!

Here's my composite, with colour adjustment based on Gordan's earlier advice:

Click to view attachment

Gordan,

Interesting indeed to read your account of assembling Cassini colour composites. With the mosaics that consist of two footprints only, my approach has always been to carefully align and join the Green raw images first, and then to use that as a geometric template for aligning the Red and Blue channels.

All of these images use RGB - I haven't actually tried the Violet filter yet, and probably wouldn't anyway, unless the Blue image was missing or corrupt. In any case, the colour adjustments you and Dilo have applied to the mosaics look great!

Cheers.