Juno perijove 4, February 2, 2017 Options

[Gerald]

PJ04 #102 in the context of #085 and #122:

(NASA / JPL / SwRI / MSSS / Gerald Eichstädt)

[Gerald]

A more complete set of rgb and methane band cylindrical map projections (10 pixels per lon/lat degree).
I've added a control mask to see alignment errors with the Jupiter spheroid shape model easier.

[Bjorn Jonsson]

The JunoCam images are in a word awesome. They are a lot more challenging to process properly than e.g. the Voyager, Galileo and Cassini images but the resulting processed images are every bit as spectacular as the images from the earlier spacecraft that imaged Jupiter. In particular the color is much better than in the Voyager data for obvious reasons.

Here are a few images processed from the image 106 raw framelets. This is the "POI: Oval BA" observation. In the three images below the effects of global illumination have been removed. The contrast and color has been exaggerated and small scale features sharpened to better reveal various features and color variations.




These images show an enormous amount of small scale details. Cloud shadows and vertical relief are clearly visible at many locations. These JunoCam images shows these features better than the best and highest resolution Voyager images do.

The fairly big oval visible in these images is one of the "string of pearls" ovals near latitude 40 degrees south; this is oval A1.

And here is a different version of these images with approximately true color and contrast. Small scale features have been sharpened slightly:



All of these images were produced by using viewing geometry information from SPICE kernels to reproject the raw framelets to a simple cylindrical map. For best results I had to make corrections to the camera pointing. I then used a 3D renderer to render perspective views of an oblate spheroid using the spacecraft's location and the camera pointing at three different points in time when JunoCam was acquiring the original framelets.

Since JunoCam has a very wide field of view (58°) these images should give a fairly good idea of what a naked eye view from Juno's location would look like. This is different from the Voyager/Galileo/Cassini images where the field of view is less than 0.5°. The images from these spacecraft are therefore more similar to what one would see through a small astronomical telescope from a distance of a few million km from Jupiter.

Juno's altitude above Jupiter was only ~14,500 km when the original images were obtained. Therefore the area covered by the images isn't particularly big. Below is a quick and dirty context view. It is based on John Rogers' PJ4 predictive map that can be seen here: https://www.britastro.org/node/8908



And finally an animation showing all of image 106. It's created using Juno's location and JunoCams' pointing when it was imaging Jupiter:
https://vimeo.com/209958488

[PhilipTerryGraha...]

Wow Bjorn! This is some absolutely incredible stuff! I am definitely not spitting hyperbole when I say this is some of the most amazing material I've seen be crafted from JunoCam data. I especially love your animation; it feels like I'm right there with the spinning lil' spacecraft

[stevesliva]

I especially love your animation; it feels like I'm right there with the spinning lil' spacecraft

Would've missed that myself-- fantastic!

Fingers crossed that the radiation environment allows about 20 of these.

[Gerald]

Well, each perijove would/should allow for dozens of different fly-over animations. This is a short 200-frame animation derived from PJ04 image #109 (south polar region), and rendered with 10 pixels per (cylindrical) degree:
 jnc_pj04_109_10px_600x600_timelapse120_200frames_decompand_sqrt_v01.avi ( 895.83K ) Number of downloads: 413

It's close to "natural" colors, and square-root encoded with respect to radiometric values.
24 fps, and one frame per 5 real seconds result in a 120-fold time-lapse.

SPICE trajectory data dumped with the NAIF/SPICE utility spy.exe, all frames rendered directly from the raw (credit for the raws: NASA / JPL / SwRI / MSSS) using these SPICE trajectories, then converted to an AVI using ffmpeg.

I'm yet a little hesitant with creating and posting renditions of this type, since these sequences would look better with an "appropriate" enhancement. And I'm not yet quite happy with my own attempts to implement "appropriate".

-- Fingers crossed, that Juno will get mission extensions until near the end of the anticipated lifetime of the hardware somewhere near 40 perijoves, hopefully with a then still working JunoCam.

[Gerald]

Here the first 170 frames of the same sequence as in the previous post, but de-Lambertianed according to the 1 bar Jupiter spheroid, and the square-root encoded resulting quotient stretched with gamma = 4.0:
 jnc_pj04_109_10px_600x600_timelapse120_170frames_decompand_sqrt_deLambert_gamma4_v01.avi ( 1013.34K ) Number of downloads: 347

Contrast is considerably enhanced by this technique, but the Lambertian light model - at least my implementation - breaks down in the twilight of the terminator, and at the limb near the terminator.
Björn Jónsson's model works considerably better. But of course, I'm ambitioned to find out where my technical limitations are regarding accurate modeling of Jupiter's lighting model.

[JRehling]

Amazing, Bjorn, and wonderful. The white ovals are fascinating – a target worthy of your skills.

[Gerald]

A 361 frames AVI version (125-fold time-lapse) of the previous pj04 #109, and an AVI fragment one night worth of CPU runtime derived from #099, #100, #101, and a very short beginning of #102. In a 45 degree width and 115 degrees height cylindrically projected strip, it shows part of the flight until minutes before closest approach.
Still with the singularity near terminator and limb from de-Lambertianing.

[Gerald]

PJ-04 animation on youtube derived from images #099 to #109.

[Sean]

PJ04 portrait based on Gerald's work...



Detail...

[Sean]

I'm constantly surprised how much detail can be gleaned from this data...

[Sean]

PJ04 portraits...testing some new blending methods.

[jccwrt]

I think I found some examples of gravity waves in PJ4-102. Juno was located over the North Temperate Belt, looking south towards the North Equatorial Belt. This image is rotated 180 degrees and enlarged 2x to help make them easier to see.

[Sean]

PJ04_109 portrait using Gerald's work...