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Juno at Jupiter, mission events as they unfold
Bjorn Jonsson
post Jul 20 2016, 11:57 PM
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QUOTE (mcaplinger @ Jul 20 2016, 09:28 PM) *
We considered putting out only the framelets containing the planet and a few surrounding ones, but raw is raw.

Good decision. Including everything (i.e. including blank framelets and not cropping the images) eliminates a lot of possible problems and confusion (for example if I want to reproject images in the future and use information like image start/stop times from the metadata).
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Gerald
post Jul 21 2016, 12:20 PM
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QUOTE (elakdawalla @ Jul 21 2016, 01:04 AM) *
I'm in need of some kind of thumbnail product I can use as a visual index to the files, so whenever you produce something that covers the entire data set, please share it with me!

Part 5 of 5.
A jpg version of the 5x-reduced overview:
Attached Image

The zip file contains two kinds of png images, an enlarged crop of Jupiter, and a reduced processed full swath, together with the applied processing parameters for each swath in a textfile with extension LBL.
(The suffix "proc005" is just for disambiguation on my local computer, since I'm testing various processing methods and parameters. I'm working with BMP files, which are converted from or to PNG, therefore the "BMP" in filenames or parameters.)
--
Two CPU cores are currently running on parts 3 and 4. If everything works as expected, I'll add these two parts in a few hours.
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Gerald
post Jul 21 2016, 04:04 PM
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Added the drafts for parts 3 and 4 to the same url as part 5.

Reduced overviews:
Attached Image
Attached Image

At first glance I saw three invalid results, the cause of which is yet to be identified.
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Don1
post Jul 22 2016, 08:45 AM
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@Gerald....In the pictures that you posted in Post #25, the edge of Jupiter appears to be blue. Gas molecules in atmospheres tend to scatter blue light, so I'm wondering if that is real or if it is an artifact of processing. If it is real, then do you think it would be possible to point Junocam towards the horizon when we get closer to the planet to see if there are any clouds or haze layers visible in the atmosphere?

My understanding is that Junocam rotates with the spacecraft, so it seems like it would be possible to take a picture when the camera sweeps across the edge of the planet.

This shot from the ISS gives an idea of what I have in mind. I know that Juno is in a higher orbit than ISS but Jupiter has a larger diameter than earth and the scale height of the atmosphere is higher, so maybe it would work out.

There's also artistic and public relations reasons to do this. The public likes novelty, and this is an angle on Jupiter which has never been seen before.

Another reason to point the camera towards the horizon would be to capture the aurora. That would probably require a fair amount of luck or clever timing, but it might be possible because Jupiter's aurora run continuously. Here is a stunning ISS aurora picture.

This sunset picture from ISS is gorgeous as well and the viewing geometry enables you to appreciate the vertical structure of the clouds. I think the low sun angle is making the clouds stand out against the background. Junocam is going to have a lot less resolution than this, but maybe Jupiter clouds are bigger.

Here's another ISS picture showing the potential of low sun angles.
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Don1
post Jul 22 2016, 09:50 AM
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One more low sun angle picture from ISS. Jupiter has these 'hot spots', which are regions of descending gas which make holes in the cloud layer. The Galileo atmosphere probe fell into one of these. This ISS picture of the eye of a hurricane gives a real 3-D sense of a hole in the clouds. I think the low sun angle and oblique view is what makes it work. Trying to time a picture to catch something like this would be hard, but maybe worth a try.
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Gerald
post Jul 22 2016, 10:29 AM
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QUOTE (Don1 @ Jul 22 2016, 10:45 AM) *
@Gerald....In the pictures that you posted in Post #25, the edge of Jupiter appears to be blue. Gas molecules in atmospheres tend to scatter blue light, so I'm wondering if that is real or if it is an artifact of processing.

It's clearly an artifact of processing. You need to know, either explicitely or implicitely, camera parameters down to 4 or 5 decimals to obtain subpixel-accurate registering. And even then, a tiny blur, be it from the camera or from processing, induces a colored margin on at least one side of Jupiter. Those images are enlarged considerably, so you see each small flaw in the color registering. I played a bit with Juno's angular velocity in terms of JunoCam interframe delay, but didn't find the perfect solution (yet).
Since there are several sensitive parameters, it's very hard and time-consuming to find a set of parameters which is optimal for all circumstances. M.Caplinger used a different approach for the movie, and just aligned the color bands without considering precisely the properties of the camera.
But I'll need the approach with the parameters for the perijove images.

"That said", Jupiter's aurora might well become visible in the RGB range, think at the (red) H-alpha line of the Balmer series. But any conclusions wrt auroras from my draft processing would be premature. Clealy visible, however, is the Great Red Spot in some images; you can see it moving within a short sequence of consecutive images. And I think, that some satellite appears occasionally even in these narrow crops; but to verify, first look into the raws in order not to confuse them with hot pixels.

RGB processing of Jupiter's horizon will be particularly difficult due to the Juno's fast motion, but I'm nevertheless confident to be able to do so.

On the Juno mission site you can lobby for features your consider as most interesting.

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Btw. give me another two hours to prepare parts 1 and 2 of the approach drafts.
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Gerald
post Jul 22 2016, 12:56 PM
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Draft processing of raw images of Jupiter approach movie, parts 1 and 2.

Reduced synopsis:
Attached Image
Attached Image
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mcaplinger
post Jul 22 2016, 02:32 PM
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QUOTE (Don1 @ Jul 22 2016, 01:50 AM) *
I think the low sun angle and oblique view is what makes it work. Trying to time a picture to catch something like this would be hard, but maybe worth a try.

We have no control over the lighting, but every image Junocam takes can potentially contain the fore and aft limb.


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Disclaimer: This post is based on public information only. Any opinions are my own.
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mcaplinger
post Jul 22 2016, 06:53 PM
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QUOTE (elakdawalla @ Jul 20 2016, 03:04 PM) *
But why limit it to just one option? I'd love to get my hands on your 800x400 versions as well!

There is a certain amount of overhead in putting the images on the missionjuno website and the advance thinking was more about the smaller number of orbital images than these big movie datasets.

That said, I expect some processed version of the approach images to show up there in the next week or so.


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Disclaimer: This post is based on public information only. Any opinions are my own.
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Gerald
post Jul 24 2016, 12:47 AM
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Although comprising only parts 1 and 5 of the approach movie, I thought, I should share these two preliminary AVI animations, simply because they subjectively look exciting to me, and kind of authentic.

One of the two versions (the smaller file) shows the approach sequence similar to the way the EDRs are encoded. This is similar to the scene as it would look like with naked eyes. In the second half features on Jupiter become visible, and satellites look faint.

The other version shows all the noisy background by stretching the images in a logarithmic way without prior background subtraction. Together with the background and compression noise, the satellites are enhanced. But consider the file being large (almost 100 MB). The three lossless images at the end of the sequence look considerably different, since they show much less compression artifacts.

I'm currently rendering parts 2 and 3. Since I'm rendering two versions, both with 10x15 degrees fov, and 120 pixels per degree, i.e. about 4-fold supersampled, it will likely take another day, before the movies will comprise the full approach sequence.
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Gerald
post Jul 24 2016, 01:30 PM
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... while rendering part 4 of the approach movie ...
Did you notice the background star (Betelgeuse / Alpha Orionis) moving into the scene?
Attached Image
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Gerald
post Jul 24 2016, 05:26 PM
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Rendition of Jupiter approach movies completed.

Edit: Added zip-files (about 800 MB) with the frames used for the animations.
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Gerald
post Jul 24 2016, 10:16 PM
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QUOTE (elakdawalla @ Jul 20 2016, 10:00 PM) *
I'd like to examine the images one by one to look for cool things like moon shadows on the planet...

Images 1392 to 1394:
Attached Image

Attached Image Attached Image Attached Image
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Phil Stooke
post Jul 24 2016, 11:13 PM
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Brilliant - well done!

Phil


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Gerald
post Jul 25 2016, 03:43 PM
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Thanks, Phil! It has been an easy exercise compared to your almost daily map updates on Mars. smile.gif

... In the meanwhile I've composed an annotated AVI animation of part 5 for download, showing shadows of Io and Europa.
The moons are faint, so you'll need a darkened environment to see them on your computer screen.
Sometimes the moons are invisible while crossing Jupiter's shadow.

Three of the annotated still frames of the AVI:
Attached Image
Attached Image
Attached Image
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