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Posted by: jasedm Apr 22 2012, 08:25 PM

The latest http://www.ciclops.org/view/7190/Rev165 article is available.

This revolution includes another 74km Enceladus flyby with infrared studies on approach and recession, and RSS as prime instrument at C/A for gravity readings over the south pole. We don't get this close to Enceladus again now until October 2015.

Also a close Dione flyby at around 8000km with some great hi-res imaging and mosaics to look forward to, and some distant Titan cloud hunting.

Posted by: jasedm May 2 2012, 05:29 PM

Initial far-encounter images have landed - Enceladus from distance, and some nice plume shots.

Can anyone explain http://saturn.jpl.nasa.gov/multimedia/images/raw/casJPGFullS73/W00074053.jpg The top half is fairly 'clean' but the bottom half is speckled with cosmic-ray hits and sundry noise - I've not seen this before, how does it occur in the same image??

Looking forward to what should be some splendid close Dione pics....

Posted by: ugordan May 2 2012, 06:54 PM

I forget the exact technical reason, but in essence the CCD readout speed overwhelmed the speed the downstream components can handle (say if the spacecraft recorder configured telemetry rate was set lower) so the lower part of the image was forced to sit on the CCD for a while longer. This increases dark current background (brightening seen visible) as well as chances of cosmic ray hits. BTW, this complicates dark current calculations for calibration quite a lot.

Chances of this happening depend on whether both cameras are active simultaneously, binning and compression mode, spacecraft telemetry pickup rates (the speed at which ISS sends packets to the spacecraft recorders, which also depends on whether other instruments are actively collecting as well).

Posted by: brellis May 2 2012, 07:37 PM

ugordan, you understand that from an armchair? In Croatia? Why haven't they hired you yet?

Posted by: ugordan May 2 2012, 07:41 PM

It's explained in the extensive Porco, et. al. paper from 2004 about Cassini's ISS. Since I had to reverse-engineer most of the official calibration code for my purposes, I kind of needed to know things like this about the cameras...

Posted by: jasedm May 2 2012, 07:50 PM

Wow! comprehensive answer ugordan, makes a lot of sense - thanks!

Jase

Posted by: stevesliva May 2 2012, 10:32 PM

Sounds like an interesting tradeoff between adding the additional complication of a dedicated buffer, or not. Since the buffer would be just another thing that could break.

Posted by: ugordan May 3 2012, 07:48 AM

There is a buffer, it's just not large enough to hold an entire unbinned frame. More on this in section 3.9.4. of the http://pubs.giss.nasa.gov/abs/po04100j.html I mentioned.

Now back to your regular science program schedule...

Posted by: Phil Stooke May 4 2012, 03:54 AM

http://saturn.jpl.nasa.gov/photos/raw/?start=1

Beautiful new pictures of Enceladus and Dione. I love the set with the big impact basin right at the top of the disk of Dione and Saturn behind it.

Phil

Posted by: elakdawalla May 5 2012, 12:08 AM

I put together just a few of the goodies from this flyby: http://www.planetary.org/blogs/emily-lakdawalla/2012/05041544.html

But I can't believe I'm the first one to post any of these, with the first images having been on the ground for more than 24 hours now. Hellooooo! This is a forum about image processing! There are so many more awesome pictures from this flyby to play with! Is anybody else out there interested in playing and sharing?

Posted by: Ian R May 12 2012, 12:05 PM

This one's for Phil and Emily ...

Posted by: Phil Stooke May 12 2012, 06:04 PM

Thanks! Very nice.

Phil

Posted by: Ian R May 24 2012, 10:53 PM

This is an enhanced IR-GREEN-UV view of a crater at 132 degrees W, 53 degrees N, which lies between the two principle arms of Arpi Fossae:

Posted by: brellis May 24 2012, 11:25 PM

Ian, I feel like I'm looking at a seashell - wow! thanks

Posted by: Ian R May 27 2012, 06:18 AM

You're welcome! I've added two more frames, turning it into a mosaic:

http://www.flickr.com/photos/10795027@N08/7277598086/sizes/o/in/set-72157624830467026/

Posted by: brellis May 27 2012, 03:20 PM

Re: Dione, I keep wondering, where are the tiger stripes? It looks so much like Enceladus!

Posted by: jasedm May 27 2012, 03:22 PM

That's a wonderful piece of work - thanks Ian!

Posted by: machi May 29 2012, 06:16 PM

Very nice and dramatic view of Dione, Ian.
It would be nice in stereo!

Posted by: Ian R Jun 8 2012, 05:41 PM

Thanks Daniel!

Here's a look at a work-in-progress mosaic that may not be completed until the data hits the PDS: