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Juno perijove 7: GRS images, July 11, 2017
avisolo
post Jul 12 2017, 09:28 PM
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GIF of latest flyover of Jupiter's Great Red Spot by NASA's Juno spacecraft:
http://i.imgur.com/JpjaO2f.gifv
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jccwrt
post Jul 12 2017, 09:39 PM
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Here's my take on Gerald's processed version. Tried not to push the contrast enhancement too far. Everything is white-balanced to the brightest clouds.

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antipode
post Jul 12 2017, 10:26 PM
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WOW! I see another area of enhanced convection/overshoot just outside the core in a vortex at the 1 o'clock position. This is gunna get good.

Could someone tell me if these high white cloudtops represent H20 or ammonia convection?

P
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Gerald
post Jul 12 2017, 11:57 PM
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Ammonia or H2O, both plausible.

PJ07, #51, 53, 54:
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Gerald
post Jul 12 2017, 11:59 PM
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PJ7, #55, and 56:
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Gerald
post Jul 13 2017, 12:02 AM
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PJ7, #57, and 59:
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Gerald
post Jul 13 2017, 12:11 AM
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PJ7, #60 (reviewed), and #61
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PNG versions, except reviewd #60 submitted to missionjuno.
The images are rendered with an assumed rotation period of 30.7007 s for Juno, and 80.96 frames per rotation. Calibration of the parameters by eye, not yet formally.

Thanks for all your derived versions! Those are really astonishing. I see, that there is always something I can learn.
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Bjorn Jonsson
post Jul 13 2017, 01:51 AM
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Wow. The GRS also has the high altitude clusters of small clouds that are so common elsewhere in the Juno images. I also suspect Juno may have succeeded in directly imaging altitude differences between bigger clouds. I get the impression that the dark areas in the GRS are lower than the brighter ones but this needs to be analyzed much more carefully.

Here is a quick and dirty crop from a 250 pixels/degree simple cylindrical map that my software is now producing; in this case it takes several hours to run. This is image PJ7_060. The image shows what I mentioned above. I'm including the bottom part here just for fun. It shows that the processing isn't complete yet. The color in the upper part of the image is preliminary but should be fairly close to true color.

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Sean
post Jul 13 2017, 02:01 AM
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Thanks for your excellent work Gerald. Here are some processed images based on yours...

PJ07_53


PJ07_61


PJ07_53 detail


PJ07_61 detail


Can't wait to see your efforts Bjorn.




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jccwrt
post Jul 13 2017, 03:53 AM
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Approaching the Great Red Spot...



And not to be outdone by the GRS, the north polar hood has a large cyclone along its southern edge:
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GS_Brazil
post Jul 13 2017, 12:08 PM
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How do I have to understand these images? I'm always under the impression that the middle of the image is exaggerated, and so the GRS seems to be much much bigger than what we would see on the traditional images. A kind of Fish-eye effect.
The 'original' ( I know this is composed and stitched from the real original R B G images ) image looks a bit more natural to me:

Is it because I'm used to rectangular images and the rounding at the top and bottom of the 'original' image as a matter look like being border of the planet?
In this context map I do see that that's not the case ...


But still, every time I see an image posted I get the impression that there's something wrong with the image scale / distortion / fish-eye effect ...

Anyhow, it's fantastic to see Gerald and Sean's work here. Amazing how much detail can be extracted from these raw images.


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Gerald
post Jul 13 2017, 12:41 PM
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A cylindrical projection of #60 looks like this:

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The panorama images I'm usually creating, are projected to spherical coordinates from the perspective of the camera near the time of the exposure, with latitudes of the frame as horizontal axis, and the equator a vertical axis in the horizontal center. This ensures, that the images are about the same resolution as the raws, or some almost constant factor of the raw resolution.
Any significant deviation from this projection distorts, enlarges, or reduces the size of the pixels in the raws, resulting in a considerable loss of information, or in excessive supersampling, both in the same image.
The horizontal fov of the above spherical projections is 60 degrees. Ther vertical fov is up to 180 degrees. JunoCam looks from horizon to horizon, from only a small altitude compared to Jupiter's diameter.
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Bjorn Jonsson
post Jul 13 2017, 01:56 PM
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QUOTE (GS_Brazil @ Jul 13 2017, 12:08 PM) *
How do I have to understand these images? I'm always under the impression that the middle of the image is exaggerated, and so the GRS seems to be much much bigger than what we would see on the traditional images. A kind of Fish-eye effect.
The 'original' ( I know this is composed and stitched from the real original R B G images ) image looks a bit more natural to me:

Is it because I'm used to rectangular images and the rounding at the top and bottom of the 'original' image as a matter look like being border of the planet?
In this context map I do see that that's not the case ...

This is a PJ-4 context map plus images from John Rogers' excellent summary of the PJ-4 JunoCam observations: https://britastro.org/node/9274
And yes, many of the processed GRS images exhibit a Fish-eye like effect due to the very large field of view. Here is for example a quick and dirty perspective render of image PJ7_60 from Juno's position when the PJ7_60 framelets were obtained. It has a field of view of 124 degrees (!), this very large FOV is needed to show all of Jupiter from limb to limb. For this not to look distorted you need to be *very* close to the screen when looking at the image.

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EDIT: And here is also a perspective render showing what this could like like as seen from the Earth. Here the field of view is very small:

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GS_Brazil
post Jul 13 2017, 01:56 PM
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QUOTE (Gerald @ Jul 13 2017, 09:41 AM) *
A cylindrical projection of #60 looks like this:

Attached Image


Gerald, thanks for the explanation. This image you are showing here looks natural to my eye, I don't see any distortion.
However, other images look very strange to me, like this one:
Approaching the Great Red Spot - Juno by Justin Cowart, no Flickr

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Bjorn Jonsson
post Jul 13 2017, 02:07 PM
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Note: I took the two perijove 7 threads ("Juno perijove 7" and "GRS images") and merged them into a single thread and renamed the resulting thread.
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