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Juno perijove 30, November 8, 2020
Gerald
post Nov 11 2020, 02:08 AM
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A few days ago, Juno performed her Perijove 30 (PJ 30) Jupiter flyby. A first set of JunoCam images was already downlinked to Earth.

From PJ to PJ, closest approach is gradually moving northward. The northern FFRs (folded filamentary regions) are going to be resoved better and better. At the same time, the northern spring time is going to reveal the north pole in visible light.

Here a glimpse at the northern circumpolar cyclones with the north polar cyclone just illuminated in the twilight:
Attached Image


Here a pair of cyclones of opposite sign presumably propelling each other slowly towards the south:
Attached Image


And here a storm particularly bright in methane band:
Attached Image
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Gerald
post Nov 11 2020, 02:13 AM
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Here a prettified version of PJ30, #19, showing FFRs:
Attached Image


Those images are post-processed versions of intermediate image products referenced here. This referenced list will be updated occasionally.
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Kevin Gill
post Nov 14 2020, 12:33 AM
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Lots of nice detail for Perijove 30 :-)


Jupiter - PJ30-17 - Detail


Jupiter - PJ30-17 - Detail


Jupiter - PJ30-17/19/21 - Cylindrical


Jupiter - PJ30-23 - Detail


Jupiter - PJ30-24 - Detail


Jupiter - PJ30-25 - Detail


Jupiter - PJ30-26 - Detail


Jupiter - PJ30-27 - Detail
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Brian Swift
post Nov 14 2020, 11:46 PM
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"Pirate Grumpy Cat" Jupiter PJ30_21 Crop, Exaggerated Color/Contrast


PJ30_26 Crop, Exaggerated Color/Contrast


PJ30_24 Crop, Exaggerated Color/Contrast

PJ30_28 Crop, Exaggerated Color/Contrast


PJ30_23 Crop, Exaggerated Color/Contrast


PJ30_11 Crop, Exaggerated Color/Contrast


Mike, is it taking longer to get PJ30 downlinked than usual, or am I just impatient?
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Brian Swift
post Nov 15 2020, 12:23 AM
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Gerald - Nice catch of the moon on the limb of PJ30_24 you posted at https://www.missionjuno.swri.edu/junocam/processing?id=9501
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Gerald
post Nov 15 2020, 01:22 AM
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Thanks, Brian! I looked at the hazes along the limb, when I noticed the moon serendipitiously providing us with a second approach to assess the optical thickness of the hazes, especially of a haze layer that appears to be almost detached.
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mcaplinger
post Nov 15 2020, 02:02 AM
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QUOTE (Brian Swift @ Nov 14 2020, 03:46 PM) *
Mike, is it taking longer to get PJ30 downlinked than usual, or am I just impatient?

I don't have the stats at my fingertips as to what "usual" means, but the DSN schedule does tend to vary a lot. There's nothing wrong that I've heard of. [edit: I would expect the rest of the images tomorrow, 11/16.]


--------------------
Disclaimer: This post is based on public information only. Any opinions are my own.
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Bjorn Jonsson
post Nov 15 2020, 09:01 PM
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Image PJ30_22 in approximately true color/contrast and enhanced versions.

Attached Image
Attached Image
Attached Image


Attached Image

Attached Image
Attached Image


Following a detailed look at many JunoCam images I recently made minor changes to the R/G/B multipliers I use to produce true color images. I also took a look at some Cassini images, groundbased images and two visible light spectra of Jupiter. I suspect the gamma of the JunoCam images differs a bit from the Cassini images. The parameters I use when removing limb darkening from the JunoCam images don't work well for the Cassini images. Limb darkening is apparently slightly more pronounced in the Cassini images; I'm still taking a look at this though.
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Brian Swift
post Nov 16 2020, 08:15 PM
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QUOTE (Bjorn Jonsson @ Nov 15 2020, 01:01 PM) *
I suspect the gamma of the JunoCam images differs a bit from the Cassini images.

Definitely want to hear more about this.
I haven't worked with Cassini images, but for JunoCam my pipeline treats decompanded values as linear up through raw value 224.
Raw values > 224 I "discard", thinking non-linear well saturation effects are coming into play.
I'd assume the Ca$$ini imaging program produced calibrated linear results.
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Bjorn Jonsson
post Nov 17 2020, 10:00 PM
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An enhanced north polar projection map from image PJ30_09 showing the area around Jupiter's north pole:

Attached Image


The map was processed to reveal faintly illuminated features near the terminator more clearly. The area near the terminator above and a bit left of the central North Polar Cyclone looks especially interesting in this image. Latitudes are planetographic.
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Gerald
post Nov 19 2020, 07:22 PM
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QUOTE (Brian Swift @ Nov 15 2020, 02:23 AM) *
Gerald - Nice catch of the moon on the limb of PJ30_24 you posted at https://www.missionjuno.swri.edu/junocam/processing?id=9501

After cross-checking with "Eyes on Juno", I think that it's Callosto.

In the PJ30 outbound red lightning search sequence, there seems to be a rather faint moon. My first candidate would be Amalthea by its size and redness, but cross-checking by position data is TBD. Here a composite of six images with some of the stars identified:
Attached Image

I'd estimate the visual magnitude of the moonlet (marked yellow) to be well fainter than 3m. Besides the small size, the fairly large phase angle will result in a low brightness.
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Gerald
post Nov 19 2020, 10:37 PM
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Observation of the south polar region is getting more challenging, but is still possible:
Attached Image

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Kevin Gill
post Nov 20 2020, 05:02 PM
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Southern fisheye view using images 39-47.


Jupiter - PJ30 - Composite
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JRehling
post Nov 21 2020, 03:57 AM
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I'l just chime in every few dozen posts to say "Wow," but I could be saying it after basically every post.
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Bjorn Jonsson
post Nov 21 2020, 10:22 PM
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An orthographic mosaic of images PJ30_22 and PJ30_23 in approximately true color/contrast and enhanced versions:

Attached Image
Attached Image


The mosaic shows a pair of vortexes that look remarkably different. The darker one is at planetographic latitude ~44 degrees north.
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