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T64 flyby
titanicrivers
post Dec 30 2009, 05:46 AM
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Raw images from the T64 Titan encounter are now up on the Cassini web site. This interesting flyby is described in Ciclops looking ahead here: http://ciclops.org/view/6082/Rev123
Some nice ISS images from the outbound montage of the Adiri region are shown below.
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titanicrivers
post Dec 30 2009, 10:18 AM
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T64 also included a passage over Titan's North pole and an opportunity to obtain SAR data over two large polar lakes (Ligeia and Punga Mare). Changes in shorelines may be found when comparing T64 SAR with SAR images of several years ago, reflecting an active N polar weather pattern with ethane-methane percipitation and evaporation. I could not quite get the SAR pass of the Spilker map http://www.unmannedspaceflight.com/index.p...st&id=19154 into a polar projection, so the figure below shows the spacecraft ground tract (taken from the mission description http://saturn.jpl.nasa.gov/files/20091228_...description.pdf ) and the position of the lakes to be evaluated.
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Decepticon
post Dec 30 2009, 06:58 PM
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As exciting as this is, I don't expect to see the SAR data till maybe this summer.
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Guest_Sunspot_*
post Dec 30 2009, 07:25 PM
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QUOTE (Decepticon @ Dec 30 2009, 06:58 PM) *
As exciting as this is, I don't expect to see the SAR data till maybe this summer.


Didn't they used to release it more frequently? Still waiting to see the SAR from T58
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volcanopele
post Dec 30 2009, 08:23 PM
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Yeah, I wouldn't put too much stock in that map, particularly for the later orbits. They changed the look direction for T64 from the looks of it, and that T65 swath, yeah, just looking at Cassini in Celestia, RADAR will definitely not be doing that...


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Juramike
post Dec 31 2009, 05:07 PM
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There's a hint of structure in the South polar haze in this image (S pole is at top) in the CL1 UV3 filtered image:
http://saturn.jpl.nasa.gov/multimedia/imag...6/N00149282.jpg

(Has S polar structure been seen before by Cassini? unsure.gif )


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titanicrivers
post Dec 31 2009, 11:27 PM
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An interesting image Mike. Wonder if its the start of a dark polar hood over the south pole. Another interesting image is N00149278. This is a NAC image with CL1 and CB3 filters taken from 1.2 milion Km on the Dec 30 outbound cloud search sequence. Clouds were found! Looks like more of the mid-southern latitude variety seen on the last flyby. Celestia (nice new grid!) locates these between 40 and 50 degrees S latitude.
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titanicrivers
post Jan 1 2010, 09:23 PM
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QUOTE (Juramike @ Dec 31 2009, 11:07 AM) *
There's a hint of structure in the South polar haze in this image (S pole is at top) in the CL1 UV3 filtered image:
http://saturn.jpl.nasa.gov/multimedia/imag...6/N00149282.jpg

(Has S polar structure been seen before by Cassini? unsure.gif )

A quick look back at the raw images from 2004 til now seems to show little or no S Pole structure in the haze layer with UV3 CL1 filter photos. The image Juramike has mentioned above is compared with a UV3 CL1 image from Oct 2004 below. The Celestia grids for each image are given and indicate a different (although not too different) spacecraft to Titan angle (the 2004 image is from closer in as well). Is this a real change or no ?! (Cassini images are rotated so N is up)
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Juramike
post Jan 2 2010, 04:18 AM
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Here a Methan-o-Vision composite of the T64 flyby image. I rotated it so that N is at top.

Attached Image


You can see the S polar structure way down as a slightly darker stain.

Here is an enhanced image made by simply subtracting the CL1 UV3 from the CL1 MT1 image. Lots of banded structure is apparent in the N and a little bit in the S. Also interesting how the cloud in the CL1 CB3 seems to correlate to a diffuse brighter zone seen in the CL1 MT1-CL1 UV3 image.

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Juramike
post Jan 2 2010, 10:29 PM
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New images recieved today. Here is a two-frame animation of the CL1 CB3 filtered images that shows high southern latitude cloud movement:

Attached Image

[animated GIF-click to animate]

The text number shift approximates the rotation displacement at the equator.

The clouds can be seen to be diving for the higher S latitudes and also moving W (in image "1" the E edge lies below the tip of the arrowhead shaped feature in SW Belet, in image "2" it lies well to the W).


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ngunn
post Jan 2 2010, 11:17 PM
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Interesting - there almost seems to be an elliptical loop forming as the cloud moves south. I know that the Coriolis effect is relatively weak on Titan, but are we seeing a hint of it here?
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Juramike
post Jan 3 2010, 12:18 AM
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I'm wondering if it's more of a downdraft kicking up the next batch of clouds. So you get kind of a wavefront emanating from the original clouds.

IIRC, this was postulated for some of the big storm clouds moving their energies around Titan in the Brown et al. telescopic observations.
Not sure if this storm system is big enough to do that or not....


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Hungry4info
post Jan 3 2010, 01:03 AM
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Some Saturnshine observations of Titan.
http://saturn.jpl.nasa.gov/photos/raw/rawi...?imageID=210736


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titanicrivers
post Jan 4 2010, 08:10 AM
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Hmm … wouldn’t cloud motion East to West be unexpected given the motion of past mid-southern latitude clouds and the super-rotating atmosphere from W to E. Clouds elongate W to E along latitude lines and tend to dissipate over hours to days. Spacecraft motion, distance and viewing geometry of clouds vs surface features should be factored in as Titan’s rotation rate is relatively slow (I calculated 42.3 km/hr at the equator) compared to Cassini’s velocity. In the image below (using the same CL1 CB3 images as Juramike above), blue arrows point to the edge of the more northerly cloud which may moving a little south but which ends still close to the 280W longitude line and may be dissipating; in contrast a cloud blob (red arrows) closer to 50 latitude appears to have elongated to the east between 12/30 and 12/31.
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OWW
post Jan 25 2010, 06:54 PM
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Groovy Hills Rising from Titan Surface
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