[X] My Assistant

[volcanopele]

The DPS conference in Pasadena is now in full swing (and I am not there). News and press releases are slowly trickling out of that conference, from New Scientist which reported on an Enceladus theory relating cosmic rays and Enceladus' jets and warm south polar region, to public releases at the Cassini JPL site, to glogger Brad Thomson reporting on the conference for the Planetary Society. So I thought I would create a thread just for Cassini news from this conference.

Enceladus
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There is already a thread regarding the Cooper et al. theory relating cosmic rays and the jets, so I won't touch on that here. Brad Thomson went to a few of the Enceladus talks and had a few interesting things to report. First, the ISS team is now moving away from the idea that the thrust faulting seen along the south polar terrain margin as well as the overall global tectonic pattern suggests that Enceladus experienced a flattening of its polar axis (due to an increasing in its rotation rate for example), and moving more toward a regional tectonism explaination. Again, any theory regarding the south polar terrain not only has to explain the appearance of that area, but also the tectonic pattern seen in other regions as well. Perhaps Nimmo and Pappalardo's diapir theory would work best here. The ISS team also reported on the leading hemisphere terrain. Only the western margin of this terrain has been observed at resolutions better than 1 km/pixel (that will change next year, IIRC), but what has been seen is reminiscent of the south polar region, with its criss-crossing network of ridges and troughs. Another example of a "south polar-like relic terrain" is south of Diyar and Sarandib Planitiae.

Brad also reported on talks given by John Spencer, Andy Ingersoll, and Feng Tian. John Spencer gave a plenary talk on the current state of Enceladus science on Monday. One interesting tidbit was that one of the Voyagers (I presume 2 since it came much closer to Enceladus) could have observed the tiger stripe sulci had it not been for an error that prevented the acquitition of high-resolutions of Enceladus. Would be curious to know the details on these observations (Phil?). Ingersoll examined the dynamics of the plumes and showed that some of the geysers point in directions different from normal to the surface (which of course complicates my vent location idents). Not sure about the continuous source comment. Maybe this has to do with CDA's need for a moon-wide source of dust in addition to the south polar source... Feng Tian's work on ejection velocities seem to further rule out sublimation as a plume mechanism.

Saturn
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VIMS has released an image, String of Pearls, which shows a pattern of cloud clearings in Saturn's northern hemisphere. These clearings maybe related to a large planetary wave at that latitude.

[djellison]

9 frames wide by 3 frames tall at 2 x 2 binning is only 3600 x 1200 on an 800 x 800 ccd.

I'd say 3976x1332 is the full image at full resolution.

Perhaps they intend to put the binned colour onto unbinnned clear filters - but in terms of the colour data - I think we have seen it in all its glory.

Doug

[ugordan]

9 frames wide by 3 frames tall at 2 x 2 binning is only 3600 x 1200 on an 800 x 800 ccd.

The CCDs are 1024x1024 pix. Galileo's SSI had 800x800.

Given the height is three footprints which is 3x512 and the size turned out at 1330, it's reasonable to assume 15% overlap between footprints. This would give 9 footprints horizontally at 9*512/1.15 = 4007, pretty close to 3976.

I'm puzzled by this image, though, the coverage wasn't 9x3, so they obviously cheated a bit at extreme edges. Keep in mind the 165 image figure takes into account multi-filtered frames (at least 3 - IR,clear,UV, plus various exposures).

So yeah, I agree with Doug, this is as good as it gets. The extreme edges are probably devoid of significant ring material anyway.

[djellison]

The CCDs are 1024x1024 pix. Galileo's SSI had 800x800.

DOH..

I actually wrote that post with 1024 x 1024 maths...then thought "Duh - Ciclops is 800 x 800 CCD's..."

0.64 Megapixels is so 1980s

Looking back at the raw jpgs - I see 7 filters for most of the patches almost all 2 x 2 binned.

IR3 short exp
IR3 long exp
VIO long
VIO short
Clear Long
Clear Short
Clear Medium Exp NOT 2 x 2 binned.

165 / 7 = 23 and a bit pointings...perhaps they dropped some of the short exposures for pointings most distant from the 'diamond ring' area.

Doug