Exquisite Saturn Images Options

[paxdan]

There are some gorgeous crescent saturn images coming down in the raws at the moment.

You can really see how oblate saturn is.

[ElkGroveDan]

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."

[ugordan]

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.

[Ian R]

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.

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.

[ugordan]

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

[Ian R]

...

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

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.