New Horizons at Io Options

[ugordan]

@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.

[stevesliva]

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

[ugordan]

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:

Europa is a triaxial ellipsoid (a: 1563 ±1 km b: 1561 ±2 km c: 1559.5 ±1 km)

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

[Bjorn Jonsson]

@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.

The Solar System Simulator uses a completely outdated airbrushed map of Europa based on Voyager data only.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:



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...

[volcanopele]

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


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.


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.


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


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.



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?


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.

[mgrodzki]

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.

[mgrodzki]

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

[JRehling]

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.

[Guest_John Flushing_*]

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?

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.

[mgrodzki]

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

[paxdan]

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

*sigh*

[ugordan]

^^^ Mega LOL at that.

[paxdan]

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?

[general]

It has been corrected

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[ugordan]

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.