Here is a graphic showing the key vectors from PIA08114.
Click to view attachment
[I just "discovered" the Measure tool in Photoshop, up until this evening I was measuring all these angles with a compass held up to the computer screen!]
Comparison with my lineup of the Medium altitude DISR with the Hi-altitude DISR "Huygens Landing Site" image.
(I just slid the picture under the vector arrows, everything matches up!)
Click to view attachment
-Mike
Full Version: Huygens News Thread
Here is the same vector comparison with titanicrivers' image. (It is an underlay.)
Again, the vectors are very close.
Click to view attachment
By this analysis, both of these mosaics match up with the Karkoschka mosaic (both in absolute and relative vector orientation).
There may be subtle differences between the two images (titanicrivers and mine) related to scale. Noway to use the Karkoschka mosaic to sort that out.
The differences in feature placement are well within walking distance to the HSL!
-Mike
Again, the vectors are very close.
Click to view attachment
By this analysis, both of these mosaics match up with the Karkoschka mosaic (both in absolute and relative vector orientation).
There may be subtle differences between the two images (titanicrivers and mine) related to scale. Noway to use the Karkoschka mosaic to sort that out.
The differences in feature placement are well within walking distance to the HSL!
-Mike
Pseudocolorized zoom of Huygens Channel with the lowest altitude DISR mosaic PIA06439
The Huygens Probe landing site is at the center of the image.
The image dimensions are approximately 14 km x 9 km.
Click to view attachment
A larger full-resolution version (6 m/pixel) is available here: http://www.flickr.com/photos/31678681@N07/3218004422/
-Mike
The Huygens Probe landing site is at the center of the image.
The image dimensions are approximately 14 km x 9 km.
Click to view attachment
A larger full-resolution version (6 m/pixel) is available here: http://www.flickr.com/photos/31678681@N07/3218004422/
-Mike
Closer and closer....
Pseudocolorized zooms of the Huygens Landing site with the lowest altitude DISR mosaic PIA06439
The image dimensions are approximately 6 km x 5 km and 3.3 x 2.6 km, respectively.
Click to view attachmentClick to view attachment
Full resolution images (at 3 m/pixel!!!) are available:
"Seconds before Landing": http://www.flickr.com/photos/31678681@N07/3218005286/
"Huygens Touchdown": http://www.flickr.com/photos/31678681@N07/3218005674/
-Mike
Pseudocolorized zooms of the Huygens Landing site with the lowest altitude DISR mosaic PIA06439
The image dimensions are approximately 6 km x 5 km and 3.3 x 2.6 km, respectively.
Click to view attachmentClick to view attachment
Full resolution images (at 3 m/pixel!!!) are available:
"Seconds before Landing": http://www.flickr.com/photos/31678681@N07/3218005286/
"Huygens Touchdown": http://www.flickr.com/photos/31678681@N07/3218005674/
-Mike
...WAY cool, Mike, thanks!
I want to join! congratulations, Mike. You did great identification work and I'm persuaded enough...
Moreover, last animation is spectacular and I would like to make a more fluid, heavy version if you agree.
Moreover, last animation is spectacular and I would like to make a more fluid, heavy version if you agree.
QUOTE (dilo @ Jan 25 2009, 04:08 AM) 
I would like to make a more fluid, heavy version if you agree.
Absolutely!
QUOTE (ngunn @ Jan 21 2009, 07:45 AM)
... I know that lots of ad hoc adjustments have been made to arrive at these results, but are they the right ones? ...
(Anybody heard anything more about the VIMS?)
(Anybody heard anything more about the VIMS?)
I think anyone who has tried to piece the DISR images together knows there is a lot of guessing about the absolute orientation. Some of the pieces don't line up, and some of them seem to repeat, but then the topography changes from image to image: Are these 2-d limitations, jpeg artifacts, or similar terrain?
Agreed !!! However a nice paper by Keller et. al. http://dx.doi.org/10.1016/j.pss.2007.11.020 referenced in previous posts provides a detailed analysis of the Huygen's landing site with respect to the DISR images, radar (from T8) and ISS. The paper discusses the HLS 'dark spot' pointing out its radar brightness. The following animation now incorporates this landmark and a scale mark and should be a more accurate mapping of radar and DISR stereographic images.
Click to view attachment
Click to view attachment
Spot on there, titanicrivers!! To the best of my knowledge, that reconstruction is VERY good
Well, for the first time that one convincingly identifies the DISR 'spooky dude' arrowhead (especially the northern edge of it) with just-visible SAR features. Is that an incidental by-product of the fit, titanicrivers, or did you use it as a constraint?
QUOTE (ngunn @ Jan 26 2009, 04:30 AM)
Well, for the first time that one convincingly identifies the DISR 'spooky dude' arrowhead (especially the northern edge of it) with just-visible SAR features. Is that an incidental by-product of the fit, titanicrivers, or did you use it as a constraint?
Turns out to be a by-product of a fit using 3 landmarks as Keller et al used in their analysis. 1) First (as you suggested) getting the dunes to the north to be flatter by despherizing the Karkoschka DISR mosaic at 20 km and matching them to Juramikes composite of T8 and T41 2) matching the radar bright area of the northern 'Huygens Island' to the river dissected central portion of that structure visualized by DISR and finally 3) superimposing the lower radar bright 'island' over the DISR dark spot. Previously I had not done the last adjustment and so did not have other structures (including the spooky dudes) in correct position. I must confess I didn't see the spooky dudes in the SAR until your comment above!
QUOTE (volcanopele @ Jan 26 2009, 03:46 AM)
Spot on there, titanicrivers!! To the best of my knowledge, that reconstruction is VERY good
Thanks VP! Lost a bit of sleep over it but it was alot of fun!
Johhny: "Well, Missus Schoolteacher, I've added up these number 3 different times."
Ms. Schoolteacher: "Very good Johhny! What was the result?"
Johnny: "I got three different answers!"
I made a layer stack with everyone's DISR/RADAR alignments: mine, titanicrivers', Soderblom et al. (Figure 1, DISR and RADAR), Keller et al. (Figure 2, RADAR and DISR).
I'm going to switch to the Keller et al. coordination because it is at a higher resolution in the article, and the arrows are finer and match up better between RADAR and DISR when enlarged. (Less than a pixel difference - the Soderblom image when enlarged was off about 15 pixels due to blur of the image at that enlargment scale)
My T8/ISS alignment is good, less than 2 pixel diff. [The gap on NE rim between the old degraded crater to the E of Huygens Landing site is the best feature to use to line stuff up.]
So putting the Keller RADAR/DISR combination on my T8 swath alignment (1.1 degree clockwise rotation of the Keller combination) lines up all the features perfectly.
Using the Keller alignment as "standard", this puts the Soderblom Huygens island at the same scale, but shifted just to the N of due W by 6.8 km (40 pixels)
My alignment is off by about 3 km (18 pixels) at 50 degrees or WSW and at the same scale.
[Oops, looks I wasn't so coordinated with Soderblom after all].
And I'm having problems getting the Karkoschka portion of the titanicrivers mosaic (the orange zone) to line up due to some sorta residual distortion.
The only way to really see this is repeated blinking back and forth between the literature images and the attempted lineups....
-Mike
Ms. Schoolteacher: "Very good Johhny! What was the result?"
Johnny: "I got three different answers!"
I made a layer stack with everyone's DISR/RADAR alignments: mine, titanicrivers', Soderblom et al. (Figure 1, DISR and RADAR), Keller et al. (Figure 2, RADAR and DISR).
I'm going to switch to the Keller et al. coordination because it is at a higher resolution in the article, and the arrows are finer and match up better between RADAR and DISR when enlarged. (Less than a pixel difference - the Soderblom image when enlarged was off about 15 pixels due to blur of the image at that enlargment scale)
My T8/ISS alignment is good, less than 2 pixel diff. [The gap on NE rim between the old degraded crater to the E of Huygens Landing site is the best feature to use to line stuff up.]
So putting the Keller RADAR/DISR combination on my T8 swath alignment (1.1 degree clockwise rotation of the Keller combination) lines up all the features perfectly.
Using the Keller alignment as "standard", this puts the Soderblom Huygens island at the same scale, but shifted just to the N of due W by 6.8 km (40 pixels)
My alignment is off by about 3 km (18 pixels) at 50 degrees or WSW and at the same scale.
[Oops, looks I wasn't so coordinated with Soderblom after all].
And I'm having problems getting the Karkoschka portion of the titanicrivers mosaic (the orange zone) to line up due to some sorta residual distortion.
The only way to really see this is repeated blinking back and forth between the literature images and the attempted lineups....
-Mike
I downloaded and installed PTLens (available here: http://epaperpress.com/ptlens/)
I used PTLens (as the Photoshop Plug-in) to do a un-fisheye effect, then several targeted Filter>Distort>Spherize (despherize) using different sized selections in the image, most centered on the HSL.
Flicking back and forth with the Keller image, I poked and prodded (resized, rotated, warped, and warped selectoins) until I was pretty happy with it.
Blinking back and forth with the Keller image, the largest difference anywhere between the two images is 10-15 pixels, about 350 m at this resolution. (I had to resize PIA08114 to 25% full to get the functions to work with my hardware.)
The full resolution is at 1920 pixels per degree, or 22.7 m/pixel.
Here is a jpeg that shows the final Karkoschka mosaic (PIA08114) now projected flat:
Click to view attachment
A larger JPEG version of this image is available at: http://www.flickr.com/photos/31678681@N07/3230059057/
The full resolution TIFF can be downloaded here (for a limited time): http://www.speedyshare.com/974501980.html
-Mike
I used PTLens (as the Photoshop Plug-in) to do a un-fisheye effect, then several targeted Filter>Distort>Spherize (despherize) using different sized selections in the image, most centered on the HSL.
Flicking back and forth with the Keller image, I poked and prodded (resized, rotated, warped, and warped selectoins) until I was pretty happy with it.
Blinking back and forth with the Keller image, the largest difference anywhere between the two images is 10-15 pixels, about 350 m at this resolution. (I had to resize PIA08114 to 25% full to get the functions to work with my hardware.)
The full resolution is at 1920 pixels per degree, or 22.7 m/pixel.
Here is a jpeg that shows the final Karkoschka mosaic (PIA08114) now projected flat:
Click to view attachment
A larger JPEG version of this image is available at: http://www.flickr.com/photos/31678681@N07/3230059057/
The full resolution TIFF can be downloaded here (for a limited time): http://www.speedyshare.com/974501980.html
-Mike
QUOTE (Juramike @ Jan 27 2009, 01:27 AM)
I made a layer stack with everyone's DISR/RADAR alignments: mine, titanicrivers', Soderblom et al.
I'd be interested to see a 3-way blink of that. I'm having trouble remembering one version when I'm looking at another.
Got it!
Here is a new "vortex distorted" image I made of PIA08114 compared with Figure 2 from Keller et al. This is a pure opaque blink, there is no transparent overlay.
Click to view attachment
There is a slight distortion in the center of Huygens channel (the Keller et al figure is slightly "bloated"?) and the N side of Huygens island is slightly stretched N.
Both effects are within 5-15 pixels (115-345 meters) of the Keller reference in the highest resolution image I've got.
To correct for the gnomonic projection, I used a series of fisheye corrections of selected areas with decreasing radii centered on the Huygens Landing Site (HSL). The idea was to reproject the Karkoschka mosaic onto a sort of vortex to result in a flat projection.
(A single fisheye correction only gives a bowl)
Here's the exact recipe of how I hacked my way through this:
1) Reduce original PIA08114 TIFF image size by 50% (otherwise my machine wouldn't handle it)
2) Apply PTLens Fisheye correction at 170
3) Select region centered on HSL with radius 1600 pixels, Filter>Distort>Spherize -5%
4) Select region centered on HSL with radius 800 pixels, Filter>Distort>Spherize -10%
5) Select region centered on HSL with radius 400 pixels, Filter>Distort>Spherize -20%
7) Select region centered on HSL with radius 200 pixels, Filter>Distort>Spherize -40%
8) Select region centered on HSL with radius of 150, Filter>Distort>Spherize -80%
9) Counterclockwise rotation of the image by -1.7 degrees
10) Increase size of image by 10%
11) Select region centered on HSL with radius of 200 pixels, Filter>Distort>Spherize -20%
12) Select region centered on HSL with radius of 400 pixels, Filter>Distort>Spherize -10%
13) Resize image (ca. 3% enlargement)
-Mike
Here is a new "vortex distorted" image I made of PIA08114 compared with Figure 2 from Keller et al. This is a pure opaque blink, there is no transparent overlay.
Click to view attachment
There is a slight distortion in the center of Huygens channel (the Keller et al figure is slightly "bloated"?) and the N side of Huygens island is slightly stretched N.
Both effects are within 5-15 pixels (115-345 meters) of the Keller reference in the highest resolution image I've got.
To correct for the gnomonic projection, I used a series of fisheye corrections of selected areas with decreasing radii centered on the Huygens Landing Site (HSL). The idea was to reproject the Karkoschka mosaic onto a sort of vortex to result in a flat projection.
(A single fisheye correction only gives a bowl)
Here's the exact recipe of how I hacked my way through this:
1) Reduce original PIA08114 TIFF image size by 50% (otherwise my machine wouldn't handle it)
2) Apply PTLens Fisheye correction at 170
3) Select region centered on HSL with radius 1600 pixels, Filter>Distort>Spherize -5%
4) Select region centered on HSL with radius 800 pixels, Filter>Distort>Spherize -10%
5) Select region centered on HSL with radius 400 pixels, Filter>Distort>Spherize -20%
7) Select region centered on HSL with radius 200 pixels, Filter>Distort>Spherize -40%
8) Select region centered on HSL with radius of 150, Filter>Distort>Spherize -80%
9) Counterclockwise rotation of the image by -1.7 degrees
10) Increase size of image by 10%
11) Select region centered on HSL with radius of 200 pixels, Filter>Distort>Spherize -20%
12) Select region centered on HSL with radius of 400 pixels, Filter>Distort>Spherize -10%
13) Resize image (ca. 3% enlargement)
-Mike
And here are Juramike's creations of the T8 and T41 composite SAR layered onto his flattened DISR image in the post above. Enjoy!
Click to view attachment
Click to view attachment
Very nice! Both imagers now seem in close agreement in the dude arrowhead area. Differences increase further westward however. To me, the DISR feature I call 'the enclosure' makes marginally more sense on the SAR where Mike has it (going on that last post), as do some of the features to the south of it. The dead straight DISR valley in the Huygens island is also differently placed relative to SAR in the two versions. I wouldn't expect the SAR to resolve it so I could believe either position.
Here is a 4-way blink GIF that shows the agreement between the DISR-RADAR alignment in Keller et al (Fig 2) and my [T8+T41] RADAR and the Vortex-modified PIA08114 DISR mosaic.
Click to view attachment
(click to animate)
(Keller et al. images reproduced with permission from the author)
(The Keller et al. images were rotated 1.1 degree clockwise and were expanded vertically by 1%)
Animation image sequence:
1) DISR from Fig. 2 Keller et al.
2) RADAR from Fig. 2 Keller et al.
3) my [T8+T41] combined RADAR alignment (some warping done)
4) my Vortex-modified PIA08114 DISR mosaic
At the 256/deg pixel view there are only subtle shifts of ca. <2 pix, corresponding to about 300 m. (As noted in previous DISR blink).
-Mike
Click to view attachment
(click to animate)
(Keller et al. images reproduced with permission from the author)
(The Keller et al. images were rotated 1.1 degree clockwise and were expanded vertically by 1%)
Animation image sequence:
1) DISR from Fig. 2 Keller et al.
2) RADAR from Fig. 2 Keller et al.
3) my [T8+T41] combined RADAR alignment (some warping done)
4) my Vortex-modified PIA08114 DISR mosaic
At the 256/deg pixel view there are only subtle shifts of ca. <2 pix, corresponding to about 300 m. (As noted in previous DISR blink).
-Mike
Here are coordinated TIFF files for rebuilding the alignment above:
(for those of y'all in a DIY mood...)
Keller et al. DISR (modified - clockwise rotated 1.1 degree): Click to view attachment
(for those of y'all in a DIY mood...)
Keller et al. DISR (modified - clockwise rotated 1.1 degree): Click to view attachment
Keller et al (Fig 2) RADAR (modified - clockwise rotated 1.1 degree): Click to view attachment
My alignment of the T8+T41 SAR RADAR combo swaths (modified and warped then averaged): Click to view attachment
My vortex-modified PIA08114 DISR mosaic (256 pixels/degree): Click to view attachment
And the ISS image of the same area (crop from PIA08399) (256 pixels/degree): Click to view attachment
Here is a Speedy-share link to a higher-resolution TIFF of the Vortex-modified PIA08114 DISR mosaic (960 pixels/degree or 46 m/pixel)
Warning 25 Mb! : http://www.speedyshare.com/938673260.html
And I've updated a JPEG version of the full-resolution image (1920 pixels/degree or 23 m/pixel) here: http://www.flickr.com/photos/31678681@N07/...157612993789757
Enjoy!
-Mike
Warning 25 Mb! : http://www.speedyshare.com/938673260.html
And I've updated a JPEG version of the full-resolution image (1920 pixels/degree or 23 m/pixel) here: http://www.flickr.com/photos/31678681@N07/...157612993789757
Enjoy!
-Mike
Reworked pseudocolorized Huygens Channel mosiac using modified PIA08114:
Click to view attachment
(improvements include better positioning of Huygens Landing site on RADAR/ISS basemap, better resolution of DISR mosaic)
Higher resolution version (256 pixels per degree, 170 m/pixel) available here: http://www.flickr.com/photos/31678681@N07/3237117943/
-Mike
Click to view attachment
(improvements include better positioning of Huygens Landing site on RADAR/ISS basemap, better resolution of DISR mosaic)
Higher resolution version (256 pixels per degree, 170 m/pixel) available here: http://www.flickr.com/photos/31678681@N07/3237117943/
-Mike
QUOTE (Juramike @ Jan 28 2009, 06:36 AM)
There is a slight distortion in the center of Huygens channel (the Keller et al figure is slightly "bloated"?) and the N side of Huygens island is slightly stretched N.
The Keller et al. figure is a gnomonic projection, perhaps that explains the 'bloating'?
Very nice work!
Reworked descent images, based on alignment mentioned above:
Huygens Landing Site: http://www.flickr.com/photos/31678681@N07/3251786781/
Bright Islands: http://www.flickr.com/photos/31678681@N07/3254958902/
Minutes before Touchdown: http://www.flickr.com/photos/31678681@N07/3255141176/
-Mike
Huygens Landing Site: http://www.flickr.com/photos/31678681@N07/3251786781/
Bright Islands: http://www.flickr.com/photos/31678681@N07/3254958902/
Minutes before Touchdown: http://www.flickr.com/photos/31678681@N07/3255141176/
-Mike
HSL zoom crop of modified PIA08114 DISR mosaic:
Click to view attachment
This image has been cropped from PIA08114, flattened through a series of expanding concentric selected areas that were despherized, then warped, and finally converted to black and white. The whole process was fiddled, fudged and hacked by myself to fit the previous lineup.
A JPEG of the full resolution image (at 0.75 m/pixel) is available here: http://www.flickr.com/photos/31678681@N07/3260516728/
Image diameter is approximately 1.9 km
-Mike
Click to view attachment
This image has been cropped from PIA08114, flattened through a series of expanding concentric selected areas that were despherized, then warped, and finally converted to black and white. The whole process was fiddled, fudged and hacked by myself to fit the previous lineup.
A JPEG of the full resolution image (at 0.75 m/pixel) is available here: http://www.flickr.com/photos/31678681@N07/3260516728/
Image diameter is approximately 1.9 km
-Mike
VIMS of the landing site here:
http://www.lpi.usra.edu/meetings/lpsc2009/pdf/1599.pdf
In view of the intense interest of a number of us here may I appeal to the authors to post a larger version of the image in Fig.1 of that abstract?
http://www.lpi.usra.edu/meetings/lpsc2009/pdf/1599.pdf
In view of the intense interest of a number of us here may I appeal to the authors to post a larger version of the image in Fig.1 of that abstract?
It appears to me (if you zoom in 300%) that the VIMS image is already at its max resolution, i.e. it wasn't downsampled for the abstract.
How right you are. With my eyesight it looks even better at 800%!
Beautiful - and bang on target.
Beautiful - and bang on target.
A couple of observations on Huygens channel features (and some other rambles).
In Fig 1b the 'enclosure' feature south of the Huygens island stands out clearly. Unfortunately there is a big black "R2" smack on top of the 'spooky dude' arrowhead. Therefore I have another request for the team - for an un-annotated version (please??) I really want to know if that feature is the same or different in nature from the 'enclosure'; Also whether VIMS distinguishes bright intra-channel features in general from the Huygens island itself.
We're still offered the interpretation that the bright highland areas represent icy bedrock mantled by bright organics, without any reason for the plains not being similarly mantled.
Is there any actual evidence, as opposed to a large weight of expectation, that the highlands are made of ice at all?
Let's suppose there is (or that the weight of expectation is too great to be reasonably challenged): here is another question. Could there be something in Titan's atmosphere that attacks exposed water ice? (Like there seems to be something that eats ammonia?) You could then imagine highlands originally formed from icy clathrate materials evolving a water-ice-poor rind over time. This would overcome the need for atmospheric miracle dust.
In Fig 1b the 'enclosure' feature south of the Huygens island stands out clearly. Unfortunately there is a big black "R2" smack on top of the 'spooky dude' arrowhead. Therefore I have another request for the team - for an un-annotated version (please??) I really want to know if that feature is the same or different in nature from the 'enclosure'; Also whether VIMS distinguishes bright intra-channel features in general from the Huygens island itself.
We're still offered the interpretation that the bright highland areas represent icy bedrock mantled by bright organics, without any reason for the plains not being similarly mantled.
Is there any actual evidence, as opposed to a large weight of expectation, that the highlands are made of ice at all?
Let's suppose there is (or that the weight of expectation is too great to be reasonably challenged): here is another question. Could there be something in Titan's atmosphere that attacks exposed water ice? (Like there seems to be something that eats ammonia?) You could then imagine highlands originally formed from icy clathrate materials evolving a water-ice-poor rind over time. This would overcome the need for atmospheric miracle dust.
Thermodynamically at least, exposed pure water ice should be "attacked" by the atmosphere to form a methane hydrate clathrate rind.
BUT, this clathrate should be spectroscopically identical* to water ice and methane.
* in theory at least, VERY VERY precise IR measurements could detect the teensy IR absorption shifts due to the vibrational constraints of the clathrate cage.
There could be an absorption-desorption/concentration of the surface clathrate rind that causes a concentration of a lag deposit, then a chemical reaction (with atmosphere, or just itself?) - the clathrate beign the agent transferring and concentrating stuff (from down deep?, subsurface flow?, or atmospheric products selectively absorbed/desorbed?).
The low temperature will be a kinetic barrier for any chemical reactions.
-Mike
BUT, this clathrate should be spectroscopically identical* to water ice and methane.
* in theory at least, VERY VERY precise IR measurements could detect the teensy IR absorption shifts due to the vibrational constraints of the clathrate cage.
There could be an absorption-desorption/concentration of the surface clathrate rind that causes a concentration of a lag deposit, then a chemical reaction (with atmosphere, or just itself?) - the clathrate beign the agent transferring and concentrating stuff (from down deep?, subsurface flow?, or atmospheric products selectively absorbed/desorbed?).
The low temperature will be a kinetic barrier for any chemical reactions.
-Mike
Ah! There you are Mike. Any thoughts on the VIMS image itself? To me it looks as though it's displaced the SAR as Cassini's best view of the landing site so far. Is it, and the interpretation in the abstract, in line with your expectations?
QUOTE (ngunn @ Feb 8 2009, 11:43 AM)
Ah! There you are Mike. Any thoughts on the VIMS image itself? To me it looks as though it's displaced the SAR as Cassini's best view of the landing site so far. Is it, and the interpretation in the abstract, in line with your expectations?
I think the DISR still has the best resolution of the landing site.
Hard to beat 30 cm/pixel!(The T8 and T41 SAR RADAR have resolutions of about 170 m/pixel; according to the abstract, VIMS is about 500 m/pixel.)
Everything seems to sorta fit, the pleasant surprise to me is that the western DISR bright spot (under the Western "R2") and the bright spot just S of the "Spooky Dude" formation (just under the Eastern "R2") are both VIMS Bright unit.
[The bright spot S of the "Spooky Dude" which I'm calling "DISR Bright Mass" is my new favorite feature.]
The Dark Spot of the S Island is just visible at the extreme SE edge of the VIMS image. It is VIMS dark blue unit.
-Mike
Here's how to make a blink with the VIMS from the abstract and the Huygens Channel combined T8+T41+DISR+ISS mosaic:
1) Download the original version of Huygens Channel Redux w vortex-modified PIA08114 DISR mosaic (256 pix per degree) at the original size (963x1450):
http://www.flickr.com/photos/31678681@N07/...117943/sizes/o/
2) Load into your favorite image processor (I use Photoshop, but Powerpoint should also work)
3) Select and Clip VIMS Figure 1b from the abstract and paste into a new layer in your favorite image processor.
4) Increase size of VIMS Figure 1b 480%, rotate counterclockwise 1 degree.
5) Line 'em up in xy and blink away to your hearts delight!
-Mike
1) Download the original version of Huygens Channel Redux w vortex-modified PIA08114 DISR mosaic (256 pix per degree) at the original size (963x1450):
http://www.flickr.com/photos/31678681@N07/...117943/sizes/o/
2) Load into your favorite image processor (I use Photoshop, but Powerpoint should also work)
3) Select and Clip VIMS Figure 1b from the abstract and paste into a new layer in your favorite image processor.
4) Increase size of VIMS Figure 1b 480%, rotate counterclockwise 1 degree.
5) Line 'em up in xy and blink away to your hearts delight!
-Mike
QUOTE (Juramike @ Feb 9 2009, 12:18 AM)
I think the DISR still has the best resolution of the landing site.
Yeah, but it isn't on Cassini.
Mike's right about the formation of clathrate by interaction of atmospheric gases with surface ice. It would indeed be very slow, but there are several billions years to do the job. There are a couple of papers which talk about this, some more recent ones by Caroline Thomas, plus the one by John Osegovic, and even a tatty old LPSC abstract by me!
Mike's also right that clathrates and ice are utterly indistinguishable from one another in the near IR. Well, at least on Titan, no thanks to that pesky atmosphere. The enclathrated methane adds absorption features, but they are in the exact same position as the gas phase. Annoyingly, one would be looking through a column of gas containing methane to make such a measurement.
This is a really important first-order question; what is Titan's crust made of? If only there was some way we could find out....
*cough*
http://dx.doi.org/10.1016/j.asr.2008.11.024
Mike's also right that clathrates and ice are utterly indistinguishable from one another in the near IR. Well, at least on Titan, no thanks to that pesky atmosphere. The enclathrated methane adds absorption features, but they are in the exact same position as the gas phase. Annoyingly, one would be looking through a column of gas containing methane to make such a measurement.
This is a really important first-order question; what is Titan's crust made of? If only there was some way we could find out....
*cough*
http://dx.doi.org/10.1016/j.asr.2008.11.024
Thanks for that!
I take it from Mike's reply and yours that there is no conceivable way (at least on Titan) to 'de-ice' the surface of a mass of clathrate, or to disguise its spectral signature. We see no ice signature in the spectrum of the bright highlands, yet the assumption persists that that is what they're made of - such a strong assumption that even the design of future instruments is based on it. What's to stop there being a kilometre or two of various types of organic material covering almost all of Titan? What's to stop the highlands being piles of wax? or soap?
I take it from Mike's reply and yours that there is no conceivable way (at least on Titan) to 'de-ice' the surface of a mass of clathrate, or to disguise its spectral signature. We see no ice signature in the spectrum of the bright highlands, yet the assumption persists that that is what they're made of - such a strong assumption that even the design of future instruments is based on it. What's to stop there being a kilometre or two of various types of organic material covering almost all of Titan? What's to stop the highlands being piles of wax? or soap?
QUOTE (ngunn @ Feb 9 2009, 07:35 AM)
What's to stop the highlands being piles of wax? or soap?
(The real giggle is that Swiss Cheese is consistent with properties of Titans surface: dielectric constant, volume scattering from a porous surface, IR absorbance similarities [some H2O, some organics], and that yellow color, too....)
Right, so definitely not lemon sorbet then?
VIMS of the landing site here:
http://www.lpi.usra.edu/meetings/lpsc2009/pdf/1599.pdf
In view of the intense interest of a number of us here may I appeal to the authors to post a larger version of the image in Fig.1 of that abstract?
The abstract of and R. Jaumann et. al. and the cogent discussion the above posts are fascinating and educational indeed. Here I Utilized the non-anotated image (Fig 1c) and have layered a slightly enhanced VIMS image to the previous animation of post #560. VIMS is layered in 20% gradient steps in this case. As discussed by juramike and ngunn in post #588, the arrowhead portion of Spooky Dude is apparent as a VIMS bright unit, dunes appear in the brownish VIMS shade and the S 'island'-DISR dark spot in (SE corner) is a VIMS deep blue unit.
Click to view attachment
http://www.lpi.usra.edu/meetings/lpsc2009/pdf/1599.pdf
In view of the intense interest of a number of us here may I appeal to the authors to post a larger version of the image in Fig.1 of that abstract?
The abstract of and R. Jaumann et. al. and the cogent discussion the above posts are fascinating and educational indeed. Here I Utilized the non-anotated image (Fig 1c) and have layered a slightly enhanced VIMS image to the previous animation of post #560. VIMS is layered in 20% gradient steps in this case. As discussed by juramike and ngunn in post #588, the arrowhead portion of Spooky Dude is apparent as a VIMS bright unit, dunes appear in the brownish VIMS shade and the S 'island'-DISR dark spot in (SE corner) is a VIMS deep blue unit.
Click to view attachment
QUOTE (titanicrivers @ Feb 10 2009, 08:09 AM)
Here I Utilized the non-anotated image (Fig 1c)
Problem is, Fig 1c includes details finer than the VIMS resolution which must therefore come from the underlying DISR image. So unless you've done some fancy subtraction of 1a from 1c I don't think we're looking at that spooky dude in VIMS independently (except through the hole in the 'R' in 1b).
QUOTE (ngunn @ Feb 10 2009, 04:28 AM)
Problem is, Fig 1c includes details finer than the VIMS resolution which must therefore come from the underlying DISR image. So unless you've done some fancy subtraction of 1a from 1c I don't think we're looking at that spooky dude in VIMS independently (except through the hole in the 'R' in 1b).
Agreed. I didn't read the caption closely enough for Fig1c. Have the authors released a Fig1b without the annotation?
I did ask in post 585 for an un-annotated version. Nothing's been volunteered so far. Maybe it's not reasonable to expect anything more before the conference itself. It's good to know the data exist, though, and someone here could always try that subtraction I mentioned.
More descent images, based on Keller et al. alignment:
Seconds before Landing (3 m/pixel): http://www.flickr.com/photos/31678681@N07/3262209024/
Huygens Touchdown (3 m/pixel): http://www.flickr.com/photos/31678681@N07/3261385063/
-Mike
Seconds before Landing (3 m/pixel): http://www.flickr.com/photos/31678681@N07/3262209024/
Huygens Touchdown (3 m/pixel): http://www.flickr.com/photos/31678681@N07/3261385063/
-Mike
Zoom of the extreme center of the PIA08114 mosaic. This has been cropped, flattened, and enlarged 2.3x and warped slightly.
Click to view attachment
The image scale is 20 cm/pixel. The entire structure at the center of the image is the size of a modest house (110 m).
Based on Karkoschka et al., Planetary and Space Sci. 55 (2007) 1896-1935. "DISR imaging and the geometry of the descent of the Huygens probe within Titan's atmosphere." (doi: 10.1016/j.psss.2007.04.019) I'm placing the touchdown point of the probe about 3/4 of the way to the north edge from the center of the image.
A full resolution TIFF is available here: http://www.flickr.com/photos/31678681@N07/3274864563/
-Mike
Click to view attachment
The image scale is 20 cm/pixel. The entire structure at the center of the image is the size of a modest house (110 m).
Based on Karkoschka et al., Planetary and Space Sci. 55 (2007) 1896-1935. "DISR imaging and the geometry of the descent of the Huygens probe within Titan's atmosphere." (doi: 10.1016/j.psss.2007.04.019) I'm placing the touchdown point of the probe about 3/4 of the way to the north edge from the center of the image.
A full resolution TIFF is available here: http://www.flickr.com/photos/31678681@N07/3274864563/
-Mike
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