I'm surprised that the reference images of Io are still from Voyager rather than Galileo. I realize that Galileo returned only a heartbreakingly small fraction of the high-resolution images of which it was capable, but I would have thought that it repeatedly covered Io at better than Voyager resolution.

I found this helpful page by volcanopele, which maps high resolution imaging, but doesn't address low resolution coverage.

TTT

EDIT: I thought some more about volcanopele's comments and put on my thinking cap. Io is gravitationally locked with Jupiter, and managing radiation levels was a challenge, so I guess most Galileo observations of Io took place outside Io's orbit and thus didn't cover the Jupiter facing hemisphere. [google, google] I'm not finding a handy orbit by orbit summary of the Galileo mission, the sort of thing that Emily does for us now. Did Galileo every observe the pro-jovian hemisphere of Io?

Here's a quick flicker gif comparing 4th rock's colorized New Horizon's shot with the Galileo image that volcanopele posted, for the much-resurfaced lower-right quadrant. Sorry for the low quality; I don't have time to reproject this right to get the geometry to match properly, so this is a quick-and-dirty affine transformation to get things close enough to compare. You can see that a lot of the changes we saw from Bjorn's composite are indeed new since Galileo. Using the USGS feature names, it seems that there have been serious changes in the Tarsus Regio, with big changes in the shapes of the Kaki-oi Patera and Masubi Fluctus. Cool!
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Thought I would take a look into Shango, perhaps the most interesting new lava flow observed in this image.

Here is a view of Shango Patera from Galileo:

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The color data is from the C21 encounter in July of 1999, and the higher resolution gray-scale data is from the I24 flyby in October of 1999. Shango Patera, its associated yellow-colored flows, and the near-by mountain, Skythia Mons, are in the zoomed in image at left. Shango Patera was only observed as active once during the entire Galileo mission, as a weak emission source during an SSI eclipse observation. From the looks of the Galileo color image above, it certainly doesn't look active: very little dark material can be seen. The patera is covered mostly in greenish material, the flows appear to be covered in yellow sulfur. The flows looks kinda like the Thor flows in the years before it blew its top in 2001. However, it looks like at some point in the recent past, the patera over flowed, and lava flowed to the south and south west in several, discrete flow lobes

Here is a zoomed in image from NH (with labels):

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Again you see Shango Patera, but it is now much darker and has two lobes. The northern lobe I presume is the patera and its immediate surroundings to the south. The southern lobe represents the two southern branches of the associated lava flows seen in the Galileo image (NOT the Southwestern flows). Like Thor in 2001, when Shango erupted, lava followed previously emplaced flows, rather than carving out a new path, though the details of the old and new flows may be different, we just have to resolution to tell. Does that mean that the conduits that fed the south western flows were cut off? A clue can be found in the Galileo images. In the earlier images, bright material surrounded the ends of the southern flows, but not the southwestern flows, suggesting that the southern flows had sublimated sulfur that were then deposited just outside the edges of the flows. Prometheus does the same thing here: http://pirlwww.lpl.arizona.edu/missions/Ga...prometheus.html . This suggests that the southwestern flows have been dormant long enough for both the flows and the flow margins to be covered over in sulfur, while the flow margins (or the SO2 anyways) of the southern flows had not, suggesting that the southwestern flow conduits had been closed off prior to Galileo.

I'm not usually prone to sentimentality(snort), but this has been kind of a remarkable day. I just came to the realization that I will probably not see the volcanoes of Io again in my lifetime after this passage. In the same day, we have a spacecraft orbiting Saturn, three circling Mars and two on the surface, one passing the same and looking through its own sails, one bound for Mercury, one at Venus, and a host of spacecraft on the surface here waiting to set out for Luna and the asteroids and beyond. Seems sorta ridiculous to get ecstatic over two pictures of a flying pizza. I only have two people in my immediate world who even remotely(but very sympathetically) get it. Their eyes still glaze over after five minutes of babbling. Thanks john_s, Alan Stern, volcanopele, and everyone else here for the ride.

X's and Oh!s.

When the moon hits your eye like a big pizza pie, that's amore!

Seriously, I echo your sentiments on these past few days. A "you are there" view on a low Mars flyby, radar and optical views of previously unseen big lakes on Titan, a long anticipated revisit to a dynamic ever-changing Io, continually changing perspectives of the capes of Victoria crater, and the usual weekly offerings from HiRISE. The only comparison that comes to mind of so many new vistas is the Voyager flybys. And that was like going to a movie theatre of the 70's with only one screen. The past few days have been like going into all the auditoriums in a multiplex cinema.

And as Alex is the Reference Librarian, Jason is the Io Tour Guide. Thanks!

Not sure how close to C/A there will be other Io obs, but Io should appear just short of twice that size later today.

Doug

I didn't think MVIC would even attempt observations of the sunlit side due to its extreme sensitivity. I was under the impression only nightside, jupitershine observations would be done?

I vaguely remember one dayside attempt with MVIC for Io being on the schedule. I think they hoped that it could pull something off in the high phase areas. I hope that some of the LORRI images contain multiple frames that can be stacked. Even if super-resolution doesn't work, it would cut down on noise.

The Galileo news archive, including weakly status reports, is a pretty good source:

http://galileo.jpl.nasa.gov/news/archive.c...=21&Incr=10


Galileo made several close passes of Io and had a real hard time: Every time the probe approached the moon it balked and dived into safe-mode...edit: well, not quite every time - there was at least one full science pass: http://galileo.jpl.nasa.gov/news/display.cfm?News_ID=1163

I grabbed your image and stretched even a bit more...
Man...That's scary!

@Bjorn:

Interestingly, I ran into the same kind of alignment problem when trying to fit a Solar System Simulator image of Europa to the image. I'm starting to think LORRI's pixels aren't perfectly square.

Or, Europa's oblate and the simulation is a sphere

I get differences on the order of >100 km in the equatorial direction for both Io and Europa. They can't be THAT oblate, can they?

From Rotation of Europa:


LORRI's ~20 km resolution by far drowns out the ellipsoid shape at these distances.

The Solar System Simulator uses a completely outdated airbrushed map of Europa based on Voyager data only. I wouldn't be surprised if it had large positional errors.

Here is what I get with my Europa map:

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Matches the NH image almost perfectly (I will be posting a higher resolution version in a different thread since this is the Io thread). The big question is the Io map - I'm hoping for accurate Voyager Jupiter SPICE kernels to eventually show up so I can make a more accurate version someday...

Now back to everyone's favorite moon...

Today, February 28, New Horizons makes its closest approach to Jupiter. There are six observations planned during this closest approach period, including 4 high resolution observation, 2 multi-spectral observations with LORRI, MVIC, and LEISA, and another stellar occultation.

Please keep in mind that these are simulations of the LORRI frames from Celestia, not the LORRI frames themselves...with one exception

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The first observation, Ihires4, shows Io's sub-Jovian hemisphere Clat=6.1 S, Clon=21.6 W) from a distance of 2,692,601 km. The resolution with LORRI would be 13.3 km/pixel. The phase angle has increase substantially since the last Io observation, Ieclipse3, yesterday. Now only a little more than half of Io is illuminated by the sun from this vantage point. However, the portion not illuminated by the sun is illuminated by Jupiter, allowing for Jupiter-shine observations.

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The second observation, Ihiresir3, shows Io's sub-Jovian hemisphere (Clat=6.0 S, Clon=25.8 W) from a distance of 2,675,561 km. The resolution with LORRI would be 13.2 km/pixel. Taken only a few minutes after the Ihires4 observation, not much has changed, but now RALPH will be getting in on the action, making multi-spectral observations.

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The third observation, Iocc2, is the second of two Io stellar occultations. No LORRI frames are planned, just ALICE observations.

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The fourth observation, Ihires5, shows Io's leading hemisphere (Clat=5.7 S, Clon=63.9 W) from a distance of 2,489,864 km. The resolution with LORRI would be 12.3 km/pixel. The phase angle continues to increase, now at 102.3 degrees. The Prometheus and Tvashtar plumes should now be easily visible along the limb. The new Shango Patera flow should also be visible. This observation is already on the ground. Hopefully, we will see it soon.

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The fifth observation, Ishine1, show Io's leading hemisphere (Clat=5.5 S, Clon=76.6 W) from a distance of 2,426,086 km. The resolution with LORRI would be 12.0 km/pixel. The phase angle will be 106.6 degrees. This multi-spectral observation is designed to examine the sub-Jovian hemisphere in Jupiter-shine with MVIC and LEISA. Is Shango still active?

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The final observation of the day, Ihires6, shows Io's leading hemisphere (Clat=5.4 S, Clon=90.0 W) from a distance of 2,364,560 km. The resolution with LORRI would be 11.7 km/pixel. Prometheus is now rotating into view.

on planetary radio last week, emily mentioned that the color images of the moons would be taken with jupitershine as the color cameras are set to sensitive for the low light at pluto. when do we get to see that? i suspect that there may be a real different look to them in jupiterlight.

volcanopele sort of adressed my question while i was posting it.

Not all is lost for good temporal coverage of Io's activity:

http://alamoana.keck.hawaii.edu/news/archive/io/index.html

Of course, we see "demonstration" images without a lot of regular follow-up. I don't know what it would take to get an Earth-based monitor of Io's activity working "around the clock", but it seems like it would be cheap compared to a mission, and since only one or two images would need to be taken per day, that leaves a lot of observation time for other targets.

Sure, the IR bands look weird, but they're better for watching the eruptions than visible light.

Webb will obviously excel for all of these purposes, but won't devote too much of its time to Io per se.

I think Earth-based observation without gaps remains an exciting possibility for Io, but I don't know whose money would pay for that.

Not right away. By my understanding, the images will have to be stored on flash drives for a while before they can be beamed to Earth.

it would seem so… damn, they should have been planning a jupiter probe ten years ago.

BBC report about the "massive 150 m, 495 ft high plume" on Io.

*sigh*

^^^ Mega LOL at that.

So I checked, and the BBC story said it was "Last Updated: Thursday, 1 March 2007, 08:24 GMT". I must've read it at almost exactly the time of the last update because i fired of a correction to them (with a link to the original JHUAPL press release) before making my post above at 8:30 am.

From the auto response:

Comments about our stories or services will be passed on to the appropriate editor. Factual or spelling errors will be corrected.

I wonder how long it will take to correct?

It has been corrected

WOW!!! Tvashtar's Plume!


Check out the third plume from Masubi at 6 o'clock, on the night side but reaching into sunlight!
Amazing, simply amazing.

COOL! Looks like their are two plume sources at Masubi.

Could we be seeing another plume at around 5:30 on the limb? There's some suspicious fuzzyness there.

I noticed that too. Can't be sure just from this image, hopefully we can say for sure when the rest of the images come down.

Some thing to look for. Good Eyes!

Here all the visible plumes as well as my candidates for additional discrete plumes so far:
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The Tvashtar eruption seems like a double plume.

Good eyes.

With out a lat-lon grid this is difficult to assess, but I'll give it a stab. Let's assume for a moment that those bumps at 5 o'clock and 5:30 are real features (they might be, they might not be, difficult to say). The bump at 5:30 might be a plume associated with the volcano Aramazd Patera. The bump at 5 o'clock I think is the mountain Euboea Montes.

The 5:30 feature definitely makes for a more convincing case than the 5 o'clock one. You're probably right on it being a mountain. The Tvashtar plume either got a weird twist or there's also something else erupting there.

WOW!! This may be the most dramatic image I have ever seen of Io's plumes. And not unexpectedly, LORRI is very sensitive - does anyone know the strength of Jupitershine on Io's nightside as compared to sunlight at Pluto?

And here is a rendering showing the viewing geometry:

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Hands up confession time... I've never really been that excited by Io (ducks to avoid slapping hand of volocanopele! ) but wow, that image is a stunner... the detail in that plume is just incredible.

Imagine what that would have been like in colour...

After closest approach, Io's quickly reduced to a waning crescent, allowing for longer exposures. While the resolution will rapidly diminish, we should be able to see numerous plumes crop up in scattered light and jupitershine. And likely with some (low resolution) color, too!

What a great week!

Really picturesque. Impressive what NH cameras can achieve with the dark Io-hemisphere in jupitershine.
Makes us hope for Pluto and Charon - even if it's much darker out there!

Btw., there are some mensae visible at the terminator, here a nice close up of such mountains imaged by Galileo:


Bye.

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Patience- there will be colo(u)r! We got a lower-resolution color scan with MVIC at the same time, but it won't be sent down for a month or more. We'll do some cool colorization then, I'm sure.

John.

Great colorization, Stu!!!
Waiting for the full picture...
(sad to think we will not see such kind of images for a while, even if with the most advanced AO telescopes the particular geometry/lighting which make possible to see such volcanoes and mountains aren't possible from Earth!)

Here is a properly shaded version with exaggerated Jupitershine showing at higher resolution what's visible in the NH image. As discussed when the first Io images appeared some changes are visible.

In addition to a texture map I used a crude elevation map where I 'manually' painted in all of Io's major mountains using a table from a paper published in Icarus (or possibly JGR - I'm too lazy to check) several years ago as a guide. In addition to the table I also used various images as a guide. This now seems to have been more successful than I thought although various 'errors' can be spotted. Various mountains and mesas are obvious near the terminator.

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For the mountain lovers, here's a graphic labeling all the mountains, except for the little guy northeast of Gish Bar Patera.

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John S. has a nice new glog entry.

Thanks, VP! Io's mountain landforms are strangely more fascinating to me than the volcanoes, but I'm biased in favor of tall stuff.

Here's a link to Schenk and Hargitai's database project for anyone interested:
Io Mountain Database

Nice work on the colorized pic, Stu!

edit: The lighting geometry on the Hi'iaka Montes looks very similar to that seen on Galileo's passes.

Here's another take on the changes at Masubi since Galileo. Comparison again is to the Galileo frame that volcanopele posted, flipping back and forth with the latest new LORRI frame. It looks like the current Masubi eruption is spewing primarily from what used to be that corner bend of Masubi Fluctus, with maybe some secondary plume(s) to the east.

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Here's my take on colorization of the latest image, using Bjorn's view for hue and saturation and using the shorter exposure raw images to add some more detail in the overexposed sunny side:

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You have to be kinda careful about colorizing high-phase Io images. Io's colors can change quite dramatically as you increase phase angle.

BTW, thanks for pointing out that the raw images are now up, including the shorter exposed images of Io.

Here is the 4 msec exposure image with Shango Patera pointed out:

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artifact or another plume?

is this above-average activity on Io or are there always 3 or more volcanoes activily spilling their guts? Amazing little moon

I'd say it's always pretty active. Maybe not huge volcanoes such as Pele or Tvashtar, but smaller ones, yes. And Io's not that small a moon either!

A "seven error game"


The image of the left comes from Celestia, I've desatrured it and darken the night side to have a good model comparison.
The differences are very small...