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Posted by: remcook Jul 4 2004, 08:57 AM

Iapetus: amazingly black-and-white

http://saturn.jpl.nasa.gov/multimedia/images/raw/raw-images-details.cfm?feiImageID=7097

Rhea:

http://saturn.jpl.nasa.gov/multimedia/images/raw/raw-images-details.cfm?feiImageID=7106

Tethys:

http://saturn.jpl.nasa.gov/multimedia/images/raw/raw-images-details.cfm?feiImageID=7107

Posted by: remcook Jul 4 2004, 08:58 AM

Mimas! Huh?! Cut in half?! why the sharp terminator (and in the first one there is also light coming from the side, but that could be from saturn)? in the scond one you see the large crater I think.

http://saturn.jpl.nasa.gov/multimedia/images/raw/raw-images-details.cfm?feiImageID=7030

http://saturn.jpl.nasa.gov/multimedia/images/raw/raw-images-details.cfm?feiImageID=7108

Dione:

http://saturn.jpl.nasa.gov/multimedia/images/raw/raw-images-details.cfm?feiImageID=7033

Posted by: Sunspot Jul 4 2004, 10:06 AM

How did they all end up overexposed lol

Posted by: djellison Jul 4 2004, 11:33 AM

This is the problem - they probabyl are not overexposed, but the stretching done - probably automatically - before they get dumped onto the web basically RUINS the pictures! GRGRGGRRGRG

Doug

Posted by: Sunspot Jul 4 2004, 11:49 AM

Reading through the RAW image FAQ it says the images haven't been processed in any way. There is also a section on why some images are over exposed.



Why is the image overexposed?

Cassini's cameras have 63 different exposure settings, from 5 milliseconds to 20 minutes. Scientists planning an observation must choose the exposure for each image taken. That can be tough if you're taking a picture of something you've never seen before. Thus, incomplete information on how bright something can be can lead to an underexposed or overexposed image.

Images can be overexposed on purpose too. If the scientist is looking for something dim next to something bright, the bright thing may be overexposed. Finally, Optical Navigation personnel use images to see where Cassini is relative to Saturn and its moons. Often they overexpose images because they need to see where these moons are in relation to the stars in the background sky.



Why does the image look sideways or upside down?

When a photographer tilts his or her camera to best fit the scene, the resulting images may appear sideways or at an angle. The same is true for Cassini - the images reflect the orientation of the photographer, in this case the spacecraft. The images on this web page have not been processed in any way, so there is no guarantee that the images will consistently show North at the top of the frame. [B]

Posted by: Sunspot Jul 4 2004, 11:51 AM

There's a lovely new wide angle shot of Saturn and its rings:

http://saturn.jpl.nasa.gov/multimedia/images/raw/raw-images-details.cfm?feiImageID=7032

Posted by: djellison Jul 4 2004, 01:38 PM

I think our man on the inside can confirm there is more detail in those images than we get to see in the 'raw' jpgs

Doug

Posted by: volcanopele Jul 6 2004, 03:46 AM

They look fine to me I think I can smuggle you a few unprocessed but non-saturated versions of those images.

Posted by: djellison Jul 6 2004, 09:10 AM

It's the difference between a botched 8bit JPG, and a lovely 12bit PROPER raw image I guess

Doug

Posted by: Sunspot Jul 6 2004, 11:17 AM

I did notice the majority of the distant pictures of Phoebe appear over-exposed. The RAW image FAQ states they haven't been processed in any way, so what exactly happens to these RAW images before they're placed on the web?

Posted by: djellison Jul 6 2004, 12:02 PM

They get..umm. processed They have to be - most of the images taken are 12bit images - and a JPG can only be 8bit - so there HAS to be processing by default. That processing is done automatically I assume - and the algorythm for it is a bit stupid - it just takes the brightest thing in the scene and makes that white, and the darkest thing in the scene and makes that black - and interpolates ( badly ) inbetween.

If it was done more intelligently, we would see moon detail - I am sure. You dont build a multi-billion $ spacecraft, fly it billions of miles, and then get your exposures THAT wrong

Doug

Posted by: volcanopele Jul 7 2004, 12:27 AM

Here is Mimas

Posted by: volcanopele Jul 7 2004, 12:29 AM

Here is Enceladus

Posted by: volcanopele Jul 7 2004, 12:31 AM

Here is Tethys. Note the N-S assymmetry.

Posted by: volcanopele Jul 7 2004, 12:33 AM

Here is Dione.

Posted by: volcanopele Jul 7 2004, 12:35 AM

Here is Rhea.

Posted by: volcanopele Jul 7 2004, 12:39 AM

Here is a view of Iapetus. Two clear filter images were taken of Iapetus, one with an exposure time to emphasize Cassini Regio and the other to emphasize Roncevaux Terra (quick quiz, which is the bright size and which is the dark side

The image amphasizes the dark side. Note the large impact basin.

Posted by: volcanopele Jul 7 2004, 12:42 AM

here is the other Iapetus image.

A note on these images, not wanting to get in trouble, I did no processing to these images other than to restretch them based on the orginal images. Any processing that you guys want to do you can do, just don't ask me, I have enough to do geometrically correcting the T0 and approach Titan images

Posted by: Pete B. Jul 7 2004, 03:58 AM

I'm curious about no post-SOI images of Hyperion so far. Wasn't it well placed, < 700,000 km, a few days ago and the resolution would have been a little better than Voyager? Maybe not released yet or not played back before conjunction?

Posted by: remcook Jul 7 2004, 06:58 AM

absolutely stunning! and these aren't even flybys yet!

glad to see Mimas looking relatively normal again

Posted by: imran Jul 7 2004, 07:19 AM

Thanks volcanopele. Nice work.

Posted by: Sunspot Jul 7 2004, 08:28 AM

Mimas is particularly impressive.

I was really excited when I heard that all the RAW images were going to be made available, but after seeing these images you posted I now realise that very few of them are going to be of any use. A search of Phoebe Narrow Angle camera images yielded 489 results but I would say there are only about a dozen of them that show surface details and look any good

I hope they can fix this problem before some of the other satellite encounters.

Also, I wish the public could ask questions at some of these JPL news conferences, most of the journalists that attend seem to be there out of obligation rather than interest and always ask dumb questions. There's always this though:

Carolyn Porco
Cassini Imaging Team Leader
CICLOPS/Space Science Institute
Boulder, CO
cpcomments@ciclops.org

Posted by: AlexBlackwell Jul 7 2004, 08:21 PM

I think Hyperion was imaged, or at least I seem to recall seeing it in the real time remote sensing pallet FOV.

Posted by: volcanopele Jul 7 2004, 08:27 PM

I searched for Hyperion images and all I could find were ones from June 22 (or thereabouts). I am working on soemthing else today, but I can try posting a better stretched version tomorrow.

Posted by: AlexBlackwell Jul 7 2004, 08:42 PM

I checked the actual sequence (SO2) file that was uploaded to the spacecraft and noticed an OPNAV of Hyperion scheduled for July 5 (Julian Date 186).

Posted by: volcanopele Jul 7 2004, 08:44 PM

okay, so it won't be on the ground till next week. Gotcha.

Posted by: pioneer Jul 7 2004, 09:07 PM

Excellent pictures of Mimas and Rhea. Will you all use those pictures to look for changes since Voyager or to fill gaps in Voyagers' coverage of these moons?

Posted by: xflare Jul 7 2004, 10:12 PM

Oh My God lol........ we finally get all the RAW images and they're ruined

Posted by: volcanopele Jul 8 2004, 02:28 AM

Actually, some of the Phoebe images ARE saturated, that isn't something the limited stretch did.