Juno Perijove 31, December 30, 2020 Options

[mcaplinger]

We've started getting images back from PJ31, but I'm not sure when they'll show up on missionjuno due to the holiday schedule.

[mcaplinger]

First nine PJ31 images on missionjuno.

[Gerald]

Draft renditions of the first 14 images are online, including the five red lightning search images.

[Gerald]

Here is a crop of a draft rendition of #10 showing a CPC with a potential lightning candidate:


Two reprojections with gamma=4:
#12:

[Gerald]

and #14:


Here, you'll find more reprojections stretched with gamma=4, after some illumination adjustment based on PJ20 images.
And here the same images radiometrically linearized only (gamma=1).

[Gerald]

We seem to be lucky enough to see the north polar cyclone being displaced from the pole by about one degree towards the day side:

[Bjorn Jonsson]

As a matter of curiosity, which values are you (and others here) using for Jupiter's equatorial and polar radius when reprojecting the JunoCam images? I'm using the 'official' values (71492 and 66854 km for the equatorial and polar 1 bar level) but have been seriously considering experimenting with modifying these values slightly.

[JRehling]

The altitudes of the highest clouds should be approximately 20 km above the 1 bar level. I'm not doing any rendering or projection of Juno images to confirm that that value would make for a better image product.

[Gerald]

Usually, I'm using the official IAU spheroid. Sometimes, I add 100 km whenever I want to ensure that the limb isn't cropped for whatever purpose. But I have degrees of freedom regarding the pointing. This time, I modified the pointing more than usual to get a reasonable limb fit, potentially due to the applied SPICE trajectory, including pointing of the s/c rotation axis, being preliminary, or by a degenerate geometry. However, the resulting map renditions were consistent up to one or two pixels near the pole for maps with a resolution of 60 pixel per degree. So, I didn't see a requirement for further adjustment.
But I'm aware of systematic errors, which I didn't fix yet. The IAU spheroid is inaccurate due to varying cloud heights and due to the zonal winds inducing a deviation of up to ~40 km. (Last time I looked for the best fit equipotential model, the data haven't been released publicly, yet. But the equipotential can be derived from published spherical harmonics.) I also don't adjust systematically for velocity aberration, which may result in errors up to about 3 or 4 pixels. There may also exist longitudinal deviations from a spheroid. In my eyes, such systematic adjustments don't make too much sense, since the uncertainty of the cloud or haze height can be several 10s of km, too, and require manual or semi-automatic adjustments in any case.

[Brian Swift]

As a matter of curiosity, which values are you (and others here) using for Jupiter's equatorial and polar radius when reprojecting the JunoCam images?

I'm currently using the defaults. Didn't see benefit when I experimented with using larger values (but my pipeline's limb fitting and processing isn't particularly sensitive to radius.)

[JohnVV]

As a matter of curiosity, which values are you (and others here) using for Jupiter's equatorial and polar radius when reprojecting the JunoCam images? I'm using the 'official' values (71492 and 66854 km for the equatorial and polar 1 bar level) but have been seriously considering experimenting with modifying these values slightly.

seeing as isis3/4 defaults to equatorial , that is what i am using .
i added the polar radius , at one point , but i did not see any difference .

[Brian Swift]

Someone at missionjuno is working this weekend. More raw data there today. PJ31 is looking great.
Here is reduced resolution exaggerated color/contrast collage of what's there so far.

[Gerald]

Part 2, drafts, reprojections roughly illumination-adjusted stretched to gamma=1, and gamma=4 relative to radiometric values. Resolution is about that of the camera.

Note a moon rising over the GRS in the drafts of #31 to #33.

[volcanopele]

Appears to be Ganymede

[mcaplinger]

Appears to be Ganymede

Io is coming in the next batch just for you, Jason! May be out there already.