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Juno perijoves 2 and 3, October 19 and December 11, 2016
MichaelJWP
post Dec 12 2016, 06:58 PM
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QUOTE (mcaplinger @ Dec 12 2016, 03:29 PM) *
We've been steadily getting Junocam data and as of now have maybe 2/3rds of it. I think everyone will be pleased with the more favorable lighting on this pass, and it looks like the tweaks we made to the compression commanding have worked. I'm not sure when this will get pushed out to missionjuno. Normally we would wait for the whole dataset to show up and the DSN schedule has been spotty, for example, we were on the 34m net at Madrid last night and the data rate is low.

On the topic of public interest, obviously nothing new has happened since PJ1 apart from the problems with the propulsion system. All of the media reports I've seen have been supportive and enthusiastic about the mission. This was the first pass for public target voting, which had fairly good participation.


Thanks - good news anyway, I certainly don't mind waiting. Looking forward to seeing the new lighting.
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mcaplinger
post Dec 13 2016, 10:51 PM
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PJ3 data posted -- https://www.missionjuno.swri.edu/junocam/processing


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Disclaimer: This post is based on public information only. Any opinions are my own.
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Gerald
post Dec 14 2016, 01:20 AM
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A very first idea of #03C00107:
Attached Image

(image: NASA / JPL / SwRI / MSSS / Gerald Eichstädt)
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Gerald
post Dec 14 2016, 02:22 AM
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Other selected and enhanced Perijove-3 images as a first impression:
Attached Image
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Gerald
post Dec 14 2016, 02:23 PM
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Preliminary PJ3 close-up RGBs, decompanded, color-corrected, square-root encoded.

Those are rendered without trajectory or (non-trivial) shape model. Spacecraft angular velocity just roughly estimated from PJ1 and Marble Movie.

Synopsis:
Attached Image


I'll try to refine this, and see whether I'll be able to create enhanced map products during the next days.
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Gerald
post Dec 14 2016, 02:32 PM
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... this is an ad-hoc attempt of post-processing with consumer image processing software:
Attached Image

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

Similar to a few posts above, but trying to enhance color.
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mcaplinger
post Dec 14 2016, 06:40 PM
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The Junocam ring image in processed form is buried on missionjuno in the submissions section: https://www.missionjuno.swri.edu/junocam/processing?id=368 and the raw data is equally buried in https://www.missionjuno.swri.edu/junocam/processing?id=369 Note that the thumbnails are black so you have to click through to the full image.

Doubt if it's worth the anticipation, I was surprised we could see it at all.


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Explorer1
post Dec 14 2016, 08:38 PM
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It's still an impressive first, seeing them from this perspective! Could any of the four inner satellites be resolved if they were in the image at the time, or would they just be points?
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mcaplinger
post Dec 14 2016, 09:07 PM
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QUOTE (Explorer1 @ Dec 14 2016, 12:38 PM) *
Could any of the four inner satellites be resolved if they were in the image at the time, or would they just be points?

I think they'd be resolved, Callisto would be about 4 pixels across if I did the math right. Turns out resolving the moons is not a big deal, we do that on every approach. Seeing useful detail on the moons is another thing.


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Explorer1
post Dec 14 2016, 09:48 PM
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Oops, I should've been more specific, I meant the four irregulars (Amalthea, etc). I know their orbits are a lot closer to Juno's perijove (~100-200 thousand km) but I'm not sure what that means considering their small size! I wouldn't expect anything like the Galileo images, but seeing their Jupiter-facing side (and constraining their orbits a bit) might be useful.
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mcaplinger
post Dec 14 2016, 10:07 PM
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QUOTE (Explorer1 @ Dec 14 2016, 01:48 PM) *
Oops, I should've been more specific...

No, I should have read your post more carefully. I guess Amalthea might be barely resolved at minimum range, but I doubt that such an image would be of any real use.


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JRehling
post Dec 15 2016, 09:12 PM
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Gerald, your work is very nice! Are you sure you didn't take it from a Van Gogh painting?
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Gerald
post Dec 16 2016, 04:13 PM
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Thanks! I felt like diving through the Mandelbrot set.
Beauty without tinitus.

I'm working on resolving some of the glitches in my software, and am confident to be able to provide a lot more of hopefully even better products over the weekend and next week.
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Gerald
post Dec 16 2016, 05:28 PM
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That's an enhanced crop of an intermediate map product derived from PJ3 image #092:
Attached Image

I'm experimenting with raw image #092 to find sw glitches. I had a bug in the calculations of the rotation matrix needed to transform between Jupiter and JunoCam frame for a given instant, which distorted the map away from a proper lon/lat frame. A small error in a fairly complex calculation. But it's sufficient, that you don't get what you intend.
I'm now presuming, that the residual non-flat brightness of my de-lamberted map products can partly be attributed to some mixing of planetocentric and planetographic code. The surface normal for de-Lamberting needs to be calculated planetographically while the map projection is planetocentric.
Of course one could work with the NAIF or ISIS3 libraries, but you learn more by going through all the technical challenges, and at some point you can't go beyond "the standard" without taking the risk to understand and do it yourself.
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Gerald
post Dec 18 2016, 06:12 AM
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This may serve as a small status update.
I'm working on PJ3 map products:
Attached Image

In the meanwhile, I've found and resolved two glitches, but there are still several more issues to be resolved. In this version, longitudes have not yet been aligned.
I'm currently trying to determine Juno's rotation period from the images. My initial estimate of 30.242 seconds didn't fit well. Therefore I've determined the pointing for each images separately for the above animation, which led to a shift of longitudes as a side effect in this approach.
A better preliminary estimate of Juno's rotation period seems to be 30.330 seconds, on the basis of PJ3 images 103 and 104. I'll narrow this further down, before rendering the first set of maps in higher resolution, which will not yet be de-Lamberted. An other issue I've to resolve is a glitch in the rotation matrix for the de-Lamberting model, and a better approximation of the surface normal.
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