Juno at Jupiter, mission events as they unfold Options

[nprev]

This topic will consist of discussion of Juno operations post-JOI until end of mission, currently anticipated in Feb 2018.

[scalbers]

Nice to see your updated large Earth view. It is true the cloud colors can vary, especially with lower sun elevation angles and when viewing near the limb. For example it's OK for the clouds right at the terminator to be a bit on the red side. The bright high clouds would be the best reference. For these there are still some effects with atmospheric scattering and absorption, though intensities of various colors should shift by only a few percent.

What is most noticeable to me though is that the ocean areas (including the sun glint) surrounding Chile/Argentina appear to have a greenish cast. I think when color does appear in this situation it would be more orangeish. At the risk of going outside the bounds of this forum, there are lots of videos available showing Earth from various geometries illustrating this that reasonably match the geometry we're seeing with Juno.

Just for fun I made a subjective adjustment to your image that hopefully changes it in the right direction (lowering green by 14% in the GIMP in "shadowed" areas):



Looking more online, I can also see data about the moon being reddish, more so in the brighter highlands.

Ah, yes, this could resolve the discrepancy. I've seen material from Earth's moon from less than a meter distance, and it looked perfectly grey. But it likely wasn't directly from the surface. If Moon's surface reddens from space weathering, then it should look reddish, consistent with the appearence of Moon in EFB01, after I've been following your advice to use Earth's clouds as white calibration targets. (One of the (large!) resulting processed EFB12 files here.) However, the color of the clouds aren't quite uniform, so this a compromise.
Since then I've applied the weights (0.74, 0.88, 1.0) for square-root encoded (r,g,b ). Stretching to red=1.0, this would correspond to (1.0, 1.19, 1.35) for square-root encoded (r,g,b ), or to about (1.0, 1.41, 1.83) for linearized (r,g,b ).

[JohnVV]

juno's location as of now
-- some pretty pictures


not much to look at YET

[Gerald]

To be honest, I'm not really sure what you're trying to do here. IMHO, the small-disc Jupiter images are not great for assessing fine-scale distortions because they don't cover a large area of the field and there's not a straightforward error metric that you can minimize, like residuals in star images would have. Unfortunately we haven't taken RGB star images because of TDI limitations, but maybe we need to look into what we could do along those lines.

Be warned that spin axis knowledge may need to be refined post JOI and PRM burns because of s/c balance changes. There's also some evidence of nutation effects that I have yet to track down.

Thanks for each bit of info!
The short answer regarding Jupiter's small disc images: Think of many of these images - or better their centroids in each band - superposed into one image: The result is kind of RGB star images with highly accurate pixel position data.
The difficulty with the small Jupiter images is, that they are on a narrow range of x-coordinates. But they are very suitable to constrain the camera parameters. Another set of Jupiter images with different x would result in a second narrow parameter subspace. Intersect both constraints, and you get a good geometric camera calibration. I may also use SPICE, and cruise and EFB images to obtain the missing constraints. I take the data as they are available; RGB star images would be helpful, too; but I'm confident to find a work around, if necessary.
[More advanced: Think also at the identity theorem for holomorphic functions as a related idea: It says, that for a certain class of functions, a function is determined by its properties of any local area.]
At hindsight, additional Earth / Moon images days or weeks before and after EFB would have been useful; next time, maybe.

[mcaplinger]

for a certain class of functions, a function is determined by its properties of any local area.

This may be true in some idealized mathematical sense, but I think for cases of real measurements with error and uncertainty, some configurations are much better determined than others.

In any event, what counts in the end is how well the images can be processed, and I look forward to seeing how your processing and that of other amateurs compares with ours.

additional Earth / Moon images days or weeks before and after EFB would have been useful...

Because of the flyby geometry and the sun-pointing spacecraft, this was simply never an option.

[JohnVV]

it has been ten days , juno is getting closer in it's orbit

[Decepticon]

Juno has started imagine correct?

[MahFL]

No NASA TV coverage of the first science pass ?
Inside 200k miles now.

[Bjorn Jonsson]

Juno's closest approach occurred several hours ago. At https://eyes.nasa.gov/dsn/dsn.html one can see that the Juno downlink is 120 kbps. This is a nice change from the previous Jupiter orbiter (Galileo) .

[JohnVV]

a repost of mine from a different forum
from 6 am EST to 1pmEST ( ut-4)

[Bjorn Jonsson]

The flyby was a success!! Jupiter at range of 703,000 km (obtained when Juno was approaching Jupiter), the best view of the polar regions since Pioneer 11:



There are more details at http://www.nasa.gov/feature/jpl/nasas-juno...s-jupiter-flyby

[Gerald]

A roughly linearized version enhances the beauty of the cloud structure:

[ZLD]

My take on the new image.

[wildespace]

Lookin' good! But what is that vertical colour banding in NASA's original image, and how did you guys remove it?

Thanks to Emily for the write up, as usual: http://www.planetary.org/blogs/emily-lakda...iter-close.html

Very curious to see Jupiter's polar regions and what kind of cloud formations are there. What if we'll find another hexagon?

[climber]

What if we'll find another hexagon?

That'll make two

[Marvin]

Saturn's north pole hexagon may be unique.

The current hypothesis says there must be a "steep latitudinal gradient in the speed of the atmospheric winds".

Also: "Polygons do not form at wind boundaries unless the speed differential and viscosity parameters are within certain margins and so are not present at other likely places, such as Saturn's south pole or the poles of Jupiter."

But, I wouldn't mind being surprised.

https://en.wikipedia.org/wiki/Saturn%27s_hexagon