Cassini Io revisited Options

[ugordan]

While playing around with some old Cassini data, specifically one used in PIA02588 release I noticed something I haven't seen publicly mentioned before (not that I've been paying too much attention!). Namely, Pele's eruption hotspot is visible in ISS infrared frames, similarly to the very cool effect New Horizons saw. It's not as spectacular being from much further out, but still it's pretty cool. Here's a montage showing a few different processings of data taken January 2nd, 2001 00:22 UTC from a distance of 10.29 million km, magnified 3x. Click image below to magnify:



As shown above, the hotspot is definitely not an artifact as it's seen in all infrared filters with decreasing brightness toward shorter wavelengths.

Here are the two standalone animated gifs featuring the best UV3 frames captured, magnified 2x. Tvashtar and Pele plumes visible. Click to load:

[volcanopele]

Yep, Pele's hotspot as well as other near-by hotspots (like Wayland, Pillan, and Reiden) have definitely been noted in eclipse data from Cassini at least:

http://gishbar.blogspot.com/2009/02/lpsc-2...-estimates.html

[elakdawalla]

Neat find, Gordan!

[ugordan]

I forgot all about those eclipse observations and that cool two-color movie, which is ironic because I was looking for good sunlit shots before and after eclipse in those very same sequences.

Still, those shots were taken completely in the darkness and the ones above are exposure-optimized for sunlit surfaces. Now that you mention it, there are 3 RGB sets with 12 sec exposure, binned 2x2 and corresponding clear frames. The color data is next to useless, especially the blue/UV filters, here's what I could coax out from one of the sets:

RGB color overlaid on a clear frame. Magnified 4x. The color data was processed to oblivion to remove noise so it's only qualitative here, but I like how Pele's glow is distinctly red. I'm not sure if it's the noise or if there really are some greenish aurora wisps around that area.

[JohnVV]

i liked those eruptions so much a made a "night map" for them
[attachment=19609:io1.jpg] [attachment=19610:io2.jpg] [attachment=19611:io3.jpg]

[ugordan]

A couple of plumes seen at the terminator, taken on January 1st and 5th, 2001. CB2+BL1 false color. The glow on Io's dark side is light scattered from the Jupiter backdrop. The sub-spacecraft points appear to be very similar.