Io, Still A Mystery Moon |
Io, Still A Mystery Moon |
Jul 15 2008, 03:47 PM
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#16
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Member Group: Members Posts: 655 Joined: 22-January 06 Member No.: 655 |
Thanks VP.
I thought I'd seen an image some time back of an Ionian crater, but I think it may have been an old Voyager shot of an Europan one (Pwyll maybe). |
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Aug 4 2014, 08:50 PM
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#17
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Member Group: Members Posts: 241 Joined: 16-May 06 From: Geneva, Switzerland Member No.: 773 |
New data for an old topic:
Three massive volcanic eruptions occurred on Jupiter's moon Io within a two-week period in August of last year. http://www.nasa.gov/jpl/news/jupiters-moon...0804/index.html "We typically expect one huge outburst every one or two years, and they're usually not this bright," said Imke de Pater, professor and chair of astronomy at the University of California, Berkeley, and lead author of one of two papers describing the eruptions. "Here we had three extremely bright outbursts, which suggest that if we looked more frequently we might see many more of them on Io." "These new events are in a relatively rare class of eruptions on Io because of their size and astonishingly high thermal emission," Davies said. "The amount of energy being emitted by these eruptions implies lava fountains gushing out of fissures at a very large volume per second, forming lava flows that quickly spread over the surface of Io." Regards, Marc. |
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Aug 24 2014, 09:24 AM
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#18
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Member Group: Members Posts: 648 Joined: 9-May 05 From: Subotica Member No.: 384 |
Io is definitely my favorite moon of Jupiter if not in all Solar System.
I was just wondering is there a possibility to acquire good images of Io once Juno gets to Jupiter in July 2016? -------------------- The scientist does not study nature because it is useful; he studies it because he delights in it, and he delights in it because it is beautiful.
Jules H. Poincare My "Astrophotos" gallery on flickr... |
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Aug 24 2014, 01:04 PM
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#19
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IMG to PNG GOD Group: Moderator Posts: 2254 Joined: 19-February 04 From: Near fire and ice Member No.: 38 |
This has been discussed elsewhere and the answer is no. Junocam is a wide angle camera - at a distance of e.g. ~500,000 km from Io Junocam's resolution is ~400 km/pixel. There will be no close flybys of the Galileans, this is a mission that's focused on Jupiter.
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Aug 24 2014, 04:04 PM
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#20
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Senior Member Group: Members Posts: 2542 Joined: 13-September 05 Member No.: 497 |
There will be no close flybys of the Galileans... Correct. In the nominal orbit the closest approach to Io is a little under 200,000 km. -------------------- Disclaimer: This post is based on public information only. Any opinions are my own.
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Aug 25 2014, 04:01 PM
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#21
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Solar System Cartographer Group: Members Posts: 10229 Joined: 5-April 05 From: Canada Member No.: 227 |
Right... but to be more specific, a previous calculation was that Io at best would appear only 16 pixels across. That's not much, but it will allow large features to be seen, including large eruption deposits. It is reasonable to expect that the small number of images we might expect from the closer passes by Io will let us see a few recent surface changes, such as the effects of the big eruptions just reported.
Phil -------------------- ... because the Solar System ain't gonna map itself.
Also to be found posting similar content on https://mastodon.social/@PhilStooke Maps for download (free PDF: https://upload.wikimedia.org/wikipedia/comm...Cartography.pdf NOTE: everything created by me which I post on UMSF is considered to be in the public domain (NOT CC, public domain) |
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Aug 25 2014, 04:54 PM
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#22
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Senior Member Group: Moderator Posts: 3242 Joined: 11-February 04 From: Tucson, AZ Member No.: 23 |
To be honest, ground-based observatories can do a better job. That being said, the IR instrument on Juno could acquire useful data over Io's polar regions.
-------------------- &@^^!% Jim! I'm a geologist, not a physicist!
The Gish Bar Times - A Blog all about Jupiter's Moon Io |
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Aug 25 2014, 05:10 PM
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#23
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Interplanetary Dumpster Diver Group: Admin Posts: 4404 Joined: 17-February 04 From: Powell, TN Member No.: 33 |
I would imagine that some of the plumes might look neat at a high phase angle even at such low resolution. I wonder if it would be possible to take some framelets of Io on a few successive rotations for stacking purposes to reduce noise and maximize usability. And it would seem that at its closest, should that be looking down at a pole, it would still be moderately useful for looking at albedo changes in those foreshortened regions.
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Aug 26 2014, 04:19 AM
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#24
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Senior Member Group: Members Posts: 2542 Joined: 13-September 05 Member No.: 497 |
a previous calculation was that Io at best would appear only 16 pixels across. The Junocam images of the Moon during Earth flyby are very similar to the best approaches of Io in terms of size and resolution. It's too early to say what the satellite encounter distances and times will look like for the real mapping orbit. By intent we don't get that close -- see http://www.trylam.com/files/AIAA_2008-7368...uno_Mission.pdf -------------------- Disclaimer: This post is based on public information only. Any opinions are my own.
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Sep 22 2015, 06:13 AM
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#25
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Member Group: Members Posts: 306 Joined: 4-October 14 Member No.: 7273 |
Sorry if this is the wrong thread, but I didn't see one about the reprocessing of Io images.
As you may know, some of the Voyager 1 images taken during the Io flyby are heavily smeared due to movement of the scan platform. Thanks to machi's tip about using the Parallel Iterative Deconvolution plugin for imageJ, I realized that some of these heavily smeared images could be restored to at least some degree. Just as Voyager 1 was about to make its closest approach, it took two three-frame longitudinal scans of the Moon, centered at around 300 degrees west and 5 degrees west. Judging from volcanopele's mosaic page, these images have a resolution somewhere around 400m/px. (Jupiter Viewer seems to output a wrong range to Io - 400,000 km - so I can't use that to calculate the resolution better). So without further ado, the deblurred mosaics: Io Longitudinal Scan 1 by Justin Cowart, on Flickr Io Longitudinal Strip 2 by Justin Cowart, on Flickr The most severe smearing was in the first frame of each sequence, so I'm guessing that's a result of imaging before the scan platform had entirely stabilized after slewing. Unfortunately I wasn't able to recover fine detail, but some of the larger features spanning several pixels have been recovered to some degree. At any rate I'm just happy to see some fresh new Io pictures I hadn't seen anywhere else on the web! |
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Sep 22 2015, 03:03 PM
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#26
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Member Group: Members Posts: 796 Joined: 27-February 08 From: Heart of Europe Member No.: 4057 |
Nice work!
In terms of freshness those aren't the first attempts to reprocessing those images. Some of older images are here. I did few mosaic, Bjorn Jönsson did few of them, Jason (Volcanopele) did lots of them (best high-res global mosaics of Io on the net) and Paul Schenk did exquisite mosaics for his Atlas of the Galilean Satellites. There are probably even more of them from other authors. -------------------- |
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Sep 22 2015, 03:39 PM
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#27
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Member Group: Members Posts: 306 Joined: 4-October 14 Member No.: 7273 |
Thanks for those links! I'd done some googling and searches though the various Io threads in this subforum for other examples of these pictures and came up empty-handed.
I'd really also like to thank you for sharing that tip about Deconvolution, using it feels like I've been turned into a wizard with magical image restoration powers! |
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Sep 22 2015, 05:00 PM
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#28
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Interplanetary Dumpster Diver Group: Admin Posts: 4404 Joined: 17-February 04 From: Powell, TN Member No.: 33 |
Amazing work! The Voyager 1 smears have been a set that I've never been able to crack. I've never been able to get rid of the smear without destroying detail visible from the part of the exposure that wasn't smeared.
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Sep 23 2015, 10:21 PM
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#29
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IMG to PNG GOD Group: Moderator Posts: 2254 Joined: 19-February 04 From: Near fire and ice Member No.: 38 |
Great mosaics! I ran into somewhat similar problems when desmearing some of the less smeared Ganymede images - maybe the scan platform motion is more irregular in these images than in the more smeared images, thus making the less smeared images more difficult to desmear (contrary to what one would expect).
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May 29 2016, 05:05 PM
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#30
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Member Group: Members Posts: 306 Joined: 4-October 14 Member No.: 7273 |
I worked on one of the approach sequences taken by Voyager 1 on March 4, 1979. I believe that these series of images was the one where Linda Moribito noticed the faint eruptive plume from Pele and discovered Io's volcanic activity.
Full-size here I got a slightly better S/N ratio on the images because there were three clear filter images, and two images through each of the filter sets. I used the OGV combination. I've boosted the brightness and contrast of the space around Io a little to make the plume a little more obvious. It's striking how much brighter Pele's plume is at UV and blue wavelengths. Is that more from the sulfur content, or is there a psuedo-auroral emission from the ionizing radiation? |
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