[X] My Assistant

[Guest_Sunspot_*]

http://saturn.jpl.nasa.gov/news/features/feature20060915.cfm

Ring scientists have been waiting for this. Finally, after more than two years orbiting Saturn, the Cassini spacecraft reaches one of the ultimate vantage points. The rings should shine with majesty worthy of the "Jewel of the Solar System."

[ljk4-1]

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

[paxdan]

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?

[DDAVIS]

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

[paxdan]

Very very nice Don. Thanks.

[DDAVIS]

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

[paxdan]

I have made a new version of the Saturn Eclipse view

yowza, that is really rather good.

[ugordan]

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:

[ugordan]

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.

[paxdan]

zOMG