Hi all,

only about two weeks ago (Nov 30, 2010), a new much improved hires map update for the icy Saturnian moon Tethys has been released by the NASA/Cassini mission.

It updates the version released in February 2010 (see PIA12560). New data collected during Cassini's Aug 14, 2010, flyby of the moon are used to fill in the far northern latitudes of the map from about 75 degrees north latitude to the north pole. Coverage also improves farther south on the side of the moon facing away from Saturn. That improved coverage starts at about 40 degrees north latitude and stretches north to the pole in the area roughly west of the large Odysseus Crater (between 160 degrees and 260 degrees west longitude).

The official map release is available at this URL:

http://photojournal.jpl.nasa.gov/catalog/PIA11673

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I felt it was worthwhile to provide a respective 16k VT-archive for Celestia (.Sci), using my F-TexTools

http://www.celestialmatters.org/users/t ... .0pre1.zip

to guarantee highest possible quality. See below for the VT download.
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For the implemented direct DXT compression of the output tiles, this version of my tools uses libnvtt 2.0.4 of the new, opensource NVIDIA texture tools from here

http://code.google.com/p/nvidia-texture-tools/

The output consists of optimized 1k x 1k tiles in highest quality DXT1 format. A quality difference compared to lossless PNG format cannot be noticed anymore by visual judgement! As a big advantage, however, the DXT tiles provide butter smooth highest resolution imaging with Celestia due to the GPU-supported decoding of DXT format.

Since I have included the respective .bin-format textures at each VT level (0..3), purists can also produce PNG-format tiles with my 'txtiles' tool very easily (in less than 5 minutes!).

Using my 'bin2png' tool, you can also restore the original 16k lossless PNG texture in no time from the corresponding level3 .bin file.

Unlike the original grayscale imaging source, the present texture has been computer-colored via GIMP, with this best ever /natural color/ Tethys image as a template:

http://photojournal.jpl.nasa.gov/catalo ... r=PIA06140

For Celestia.Sci, I am also considering to use Dr. Paul Schenk's new enhanced colors of the medium sized Saturnian moons as color templates for my hires textures.

(Welcome at CM, Pau! )
http://stereomoons.blogspot.com/2010/11/new-moons.html

The subtle enhanced colors beyond visual perception, provide a much more direct visualization of geological processes in the solar system, for example.
The colorful splotches and bands on the icy moons' surfaces are believed to testify from bombardments large and small.

Using a much extended (scientific) color concept (for DSOs and solar system bodies) along with wavelength filtered imaging is an essential new approach in my forthcoming Celestia.Sci distribution.

Here is an example of Dr. Schenk's enhanced Tethys colors:


In visual observation, Tethys appears VERY bright (see natural color photo above), which tends to hide the great details of the surface. So, as a compromise, I brightened the official Nov 2010 Tethys texture somewhat, but still kept it darker than the photographic images suggest.

+++++++++++++++++++++ Download of 16k VT-set ++++++++++++++++++++++
In order to include my 16k Tethys VT archive into Celestia, just unzip it in the extras folder.

http://www.celestialmatters.org/users/t ... b_DXT1.zip
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Finally, here is a flavor of how my new hires Tethys VT set looks like in Celestia:

Click for big size, please do so!


Click for big size, please do so!

Click for big size, please do so!

Click for big size, please do so!


Enjoy,
Fridger

Excelent work !
It's beautiful.

Thanks...

Fridger

_________________

Once again, the Good Doctor's work shines extraordinarily on my PC.
Many thanks for your efforts Fridger. As always, your work here is much
appreciated by the Brain-Dead.

P.S. - When can we expect completion of the Celestia.sci project? Can
hardly wait now.

Hello Bob,

thanks for the encouragement.

Good to read you over here from time to time! I hope your health is fine and your super-bike is still running with you through Germantown and neighborhood (also in winter??)...

Still no concrete predictions for the release of Celestia.Sci. As you know, it's yet a one-man effort. And that man is sometimes lazy

Chers,
Fridger

I'm downloading your huge pack...

But it's only about 450 MB. With a reasonably recent and widespread DSL setting (2 MB/sec) it only takes 225 sec = 3.74 minutes. It definitely took me longer to create the archive

Are you still using a modem?

Fridger

Ehhhhh... I'm in Italy: DSL setting of 7 MB/sec never runs beyond 256 Kb/sec.

_________________
Never at rest.
Massimo

F.

No, thank YOU for these marvelous textures.


I am here at least once a day, and both of my Harley's are being ridden as long as the snow is off of the ground.


That is alright with me since you base all of your work in science, and since the quality of this work is always amazing to me. Take your time and have a very happy Christmas.

Take care, Bob

No biking over here, as you can see from this view into our garden 5 minutes ago





Happy Christmas to you, too...

Chers,
Fridger

No kidding! I'm in the backyard of Argentina and downloaded it in 15 minutes.

I made this texture myself when it came out, but only 8k from the original 11k. I want to check it against F's 16k.

Felices Fiestas, everyone!

G

Hi Guillermo,

yes, given the 11k original size, one has this decision of "8k vs 16k" to make. I used to be very strict about never scaling UP. Yet by scaling down to 8k, some extra info contained in the 11k texture will be lost. The excellent quality of the cubic image scaling in GIMP has more recently made me more courageous as to scaling UP.

Good you will be making a comparison.

Fridger

I made quick comparison and the diference is very subtle. Unfortunately, my choice of brightness was very different from yours (I like to have shiny ice moons) so a layers "difference" in photoshop wasn't very informative.

Unlike as it sounds, it has also been snowing around here. Last Friday is even snowed in the city (800 m a.s.l.). No accumulation, though. Yesterday morning there was fresh snow on the mountaintops. Today it's sunny, fortunately. I hope it stays so until the solstice, so we can enjoy the eclipse.

G

_________________
Guillermo Abramson
Bariloche, Argentina

yes, I also emphasized this problem of brightness vs. surface detail above in my first post. Usually, I rendered the smaller sized textures of the icy Saturn moons very bright as well, in agreement with the available photos. I felt, however, that it would be a pity to miss the amazing amount of detail in a texture as large 16k, by adding so much brightness. A comparison of your 8k and my 16k textures can at best show some (visual) difference in resolution of fine details on the surface. E.g. looking at the smallest sized craterlets...

In Celestia.Sci things will be quite different, since I implemented there a much more general approach to color and wavelength filtering. So there are no problems of enjoying BOTH aspects (detail vs. natural appearance) in visualization.

Is your 8k Tethys a VT set? If yes, did you use my tools for tiling? PNG or DXT format?



But you have SUMMER now down there? It never snows here during summer, except perhaps an occasional snow shower in April when spring is still fighting with winter to some extent...So are you still in the spring season?

Fridger