Saturday, February 12, 2005
Friday, February 11, 2005
I've attempted some photometric corrections of the Huygens images, similar to what Rene has done, by flatfielding each image to remove issues created by the DISR CCD. The above mosaic has not been in the least bit geometrically corrected so take the matching with a giant grain of salt, but I think the flat-fielding attempts, which are best seen at the tops of each frame, seem to have been worth it.
- Rhea's ray system. This view is very similar to one released back in November.
- Dione's Padua Linea
- Gibbous View of Titan in clear filter
- Dione's Aeneas and Dido craters
This new raw image of Tethys taken Wednesday prominently shows Odysseus crater, the north-south albedo assymmetry, and a crater discovered last year near Tethys' south pole.
This medium resolution view (~6 km/pixel) of Tethys taken last month shows a cresent Tethys with the southern end of Ithaca Chasma in full view. Ithaca Chasma is a long fracter that runs 3/4 of the way around this mid-sized icy moon. While lower resolution than a few other views taken of Tethys, this is one of the best views of this region of the moon.
Thursday, February 10, 2005
CICLOPS has released a newly processed view of Mimas taken last month shortly after the Huygens landing on Titan. This view shows Herschel (named after the discoverer of Mimas) straddling the sunset terminator, with the central peak just poking up into view. A very dramatic view of Mimas. Cassini's next close pass of Mimas will take place on April 15.
Wednesday, February 09, 2005
Cosmic Rocker over at the MER Forum has posted a couple of anaglyphs based on the stereo pairs released by the DISR team this past weekend. These two show areas where I suspect topographic features can be seen. When rotated as I have them in the preview pic above, the topographic features show up. When rotated as Cosmic Rocker has them, I'm not so sure. So definitely the jury is still out on these features. Regardless, these anaglyphs are very well done, so I thought I would share them here.
Another useful application of the Doppler Wind Experiment data is to figure out exactly where Huygens landed. Although maps showing a location for Huygens' landing site have been published, Cassini-Huygens scientists privately express doubt that the dot marks the right spot. The three-dimensional profile of Huygens' motion that will eventually be produced from the Very Long Baseline Interferometry observations should allow scientists to pinpoint exactly where Huygens landed by tracing its path from its entry point to the surface. Preliminary calculations from the zonal wind profile released today suggest that the landing site "is going to be a good 100 or 150 kilometers [60 to 90 miles] from where we went in," Bird says. "We dropped 150 kilometers, and I have a feeling that we drifted about that same amount in the easterly direction."
CICLOPS has a released a newly processed image of Enceladus taken last month. This view reveals a very young surface almost no craters (at least none 5 km in diameter or larger). This view is but a preview of things to come as Cassini will flyby this mysterious moon next week, taking images 200 times better than this view. For an unsharpened version, try the entry for this image on the JPL Raw Images page.
Tuesday, February 08, 2005
Link of course is in the title...
CICLOPS has released a true-color version of a view showing Mimas against the backdrop of the ring-shadowed, Saturnian northern hemisphere. CICLOPS posted the IR1 (752 nm broadband) filter version last week. The blue color of Saturn's northern hemisphere results from the relative lack of clouds, allowing sunlight to penetrate farther in the its atmosphere. CICLOPS also released a more head-on view of that region of Saturn. These views of Saturn are really quite beautiful.
In finding that they released this document, the Cassini homepage had linked to their products page, in addition to the document itself (as I did with the title above). At this site, there are lectures on CIRS science at Iapetus and Phoebe and a presentation on Iapetus in general. So those might be worth checking out.
UPDATE: Interestingly enough, not much info is included on the Enceladus encounter next week...
Monday, February 07, 2005
So without further ado:
As posted here on Saturday, the DISR team has posted a few stereo pairs showing topography (or lack thereof) in the Huygens landing site region. I commented about a number of topographic features that seem to not be confirmed by others on the net, such as those who post on the #space IRC channel over at freenode.net. So I would like to further elaborate on the features I see in Stereo A and D pairs. I am convinced they are real since the plateau that is overlapped in both appears to me as a plateau in both pairs in the same shape, a plateau that slopes to the east (up in both pairs). This view is also supported by the channels that cross-cut this plateau which appear to run toward the delta near the top of stereoD.
I have made a few jpegs that show both stereo pairs and outline topographic highs in red. The blue outline represents further topographic highs on the plateaus.
CICLOPS has released a newly processed crescent view of Enceladus. This image was taken shortly after the Huygens landing last month. Believe it or not, but that is a true color view. Apparently Enceladus is pretty monochromatic at high phases (or at least this area of Enceladus). Geologically, there is an interesting ridge feature running from the limb to the terminator, reminicent of the double ridges found on Europa or Triton, or the "landing strip" feature seen by Huygens on Titan. Cassini will get a great view of the "Voyager 2" region of Enceladus next week.