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Juno PDS data
JohnVV
post Feb 6 2019, 01:38 AM
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isis3 remaps images - there is no back to camera mapping (map2cam) for juno images

the Earth fly by image "JNCE_2013282_00C00102_V01"

Attached Image


--- edit ---

for some unknown reason the jpg's of the tiff images are not uploading
-- so on to imagebox
Simple cylindrical ( color is over saturated )

ortho( color is over saturated )

BlueMarble -- in the same ortho projection for comparison
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Brian Swift
post Feb 6 2019, 05:12 AM
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QUOTE (JohnVV @ Feb 5 2019, 05:38 PM) *
...
ortho( color is over saturated )

Thanks for posting these, they answered my question.
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mcaplinger
post Feb 6 2019, 11:28 PM
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QUOTE (Brian Swift @ Feb 4 2019, 11:00 PM) *
I believe the Junocam visible limb is at a higher elevation than the 1-bar limb returned by SPICE.

The image below shows per-channel overlays of the limbs of Io and Jupiter as predicted by our best current model for PJ16-011, no timing adjustment other than our nominal recommended one. The Io limb is pretty close to dead on (maybe a pixel off in the red) and the Jupiter limb is clearly low relative to the observed limb by 4 pixels or so. So that does support the idea that what we see is higher than the limb defined by the IAU radii in the SPICE planetary constants file. Of course, the observed limb is not super-sharp so it's a judgement call about where it is exactly.

Attached Image


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volcanopele
post Feb 12 2019, 04:06 PM
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Juno data (including JunoCAM but excluding JIRAM) for PJ13 and PJ14 is now in the PDS:

https://pds.nasa.gov/datasearch/subscriptio...-20190211.shtml


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Bjorn Jonsson
post Feb 13 2019, 12:39 AM
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QUOTE (Brian Swift @ Feb 5 2019, 07:00 AM) *
QUOTE (Bjorn Jonsson @ Oct 13 2018, 12:53 PM) *
This is exactly what I've been doing. Following this I also do limb fitting of the last image containing the limb and then adjust the interframe delay slightly if necessary (I typically end up with values like 0.3711 or 0.3708 or something like that instead of 0.371). ...

As a 'sanity check' it would be interesting to know which START_TIME value you got for an image or two, especially for images obtained at an altitude of ~25,000 km or closer.

Instead of limb fitting for start time and inter frame delay, have you considered fitting for start time and planet radius?

I believe the Junocam visible limb is at a higher elevation than the 1-bar limb returned by SPICE.
For example, in the occultation of Io in PJ16_11, SPICE (Web GeoGalc) predicts a start time of 2018-10-29T20:50:43.855
which is almost a second later than the image time of frame 8, 20:50:42.932. However, the image shows the
visible limb already covering about 1/3 of Io.

I briefly considered fitting for the planet radius but decided not to for several reasons. The biggest reason is that I suspect the cloud altitudes vary depending on cloud 'type' (light or dark). In particular the bright, white ammonia clouds should usually be at a higher altitude than the darker clouds. In other words, if this correct Jupiter's shape is slightly 'irregular' if you define Jupiter's radius by the top of the visible clouds and not by a specific pressure level. I think I may have seen tentative evidence of variable cloud altitudes at the limb in some images but I'm not completely sure yet and need to look further into this. Another possible source of errors is that a reconstructed SPK kernel doesn't become available until several weeks after a a flyby. I have yet to compare the reconstructed SPK kernels to the predict kernels that become available immediately.

QUOTE (Brian Swift @ Feb 5 2019, 07:00 AM) *
I've only done a few fits since my process isn't fully automated yet, but here are some preliminary results:

Radius increase (km), start time adjustment, image id, frame numbers used for fit, filter
95 -.013 PJ14_19 7,31 green
47 -.004 PJ14_25 13,29 green
45 -.004 PJ14_25 7,35 green
90 .0015 PJ16_11 7,31 red
95 .0020 PJ16_11 8,33 green
90 .0005 PJ16_11 12,33 blue


I have no reason to expect the height variation to be uniform across Jupiter, and can think of enough potential effects on it to eliminate any desire on my part to attempt to model it.

This is very interesting and I'll probably do some processing runs to see if I get similar results (I hadn't processed these exact images yet). I'm especially interested in the start time adjustment.

QUOTE (Gerald @ Feb 5 2019, 02:42 PM) *
We don't know the exact pressure of the level of the cloud tops.

And also the cloud tops are probably not at the same pressure level everywhere - see above.

QUOTE (mcaplinger @ Feb 6 2019, 11:28 PM) *
The image below shows per-channel overlays of the limbs of Io and Jupiter as predicted by our best current model for PJ16-011, no timing adjustment other than our nominal recommended one. The Io limb is pretty close to dead on (maybe a pixel off in the red) and the Jupiter limb is clearly low relative to the observed limb by 4 pixels or so. So that does support the idea that what we see is higher than the limb defined by the IAU radii in the SPICE planetary constants file. Of course, the observed limb is not super-sharp so it's a judgement call about where it is exactly.

Attached Image

Big thanks for posting these, I've been wanting to see something like this for some time. Typically, the errors I'm getting at Jupiter's limb are similar to this when I adjust the start time using the recommended values but the fuzziness of the limb often complicates matters and makes it difficult to locate the cloud tops.
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Brian Swift
post Feb 13 2019, 07:40 AM
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QUOTE (Bjorn Jonsson @ Feb 12 2019, 04:39 PM) *
Another possible source of errors is that a reconstructed SPK kernel doesn't become available until several weeks after a a flyby. I have yet to compare the reconstructed SPK kernels to the predict kernels that become available immediately.

I believe there was a change of about 8ms on PJ16_11 (Scratched my head for bit trying to figure out why I wasn't getting the same result I had produced earlier, and eventually realized I'd update the SPK at some point).

FWIW, in my matching code I gradient filter the image and define the limb as the maximal gradient.
QUOTE
This is very interesting and I'll probably do some processing runs to see if I get similar results (I hadn't processed these exact images yet). I'm especially interested in the start time adjustment.

The start times could all easily be off by a constant since my model uses its own spacecraft to camera frame transform matrix. (I haven't checked to see how much z-rotation difference there is between mine and the standard matrix).
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Brian Swift
post Feb 23 2019, 08:00 AM
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Update to Juno3D pushed to https://github.com/BrianSwift/JunoCam/tree/master/Juno3D
  • Produces Python commands to automate Blender rendering configuration
  • Updated bias/gain masks
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Brian Swift
post Mar 11 2019, 04:32 PM
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Mike, I just noticed that prior to PJ10 TDI=1 was rare (TDI=2/3 typical), but from PJ10 forward TDI=1 seems to be the default.
I'm just curious, can you comment on the motivation for the change?
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mcaplinger
post Mar 11 2019, 05:53 PM
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QUOTE (Brian Swift @ Mar 11 2019, 08:32 AM) *
can you comment on the motivation for the change?

Higher signal levels due to the evolving sun angle.

We are still using high TDI for some of the polar images in an effort to see the circumpolar cyclones better.


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