Juno Perijove 58, February 3, 2024 Options

[mcaplinger]

(Started a new thread to avoid cluttering up the PJ57 thread with PJ58 discussion.)

[mcaplinger]

maybe they meant the area covered in Jupiter-shine? Because it would be fairly complimentary to the PJ57 coverage, getting more of the southern hemisphere coverage compared to the northern hemisphere coverage of PJ57. I'm looking forward to seeing East Kanehekili (-18/24) at visible wavelengths, as an example.

I'll do what I can. There are a whole bunch of constraints. Io goes through the FOV rapidly around 17:50 and we can only command a maximum of four images at fixed cadence before incurring a 30s delay. I can't improve the nightside coverage at the cost of degrading the dayside, the best of which happens around 17:51:30.

I'm surprised that people are getting a lot out of the TDI 2 nightside images. I guess they're better than nothing but I was expecting at least TDI 6 would be required if not more, which means the dayside would be blown out for sure.

[StargazeInWonder]

I guess to put this imagery to a rubber-meets-the-road standard, the question of how much Io is changing over the cadence of 1979-2024 (and into the future at a similar timescale) is a key parameter. If at some level of regional imagery we see a change occur and this is our one opportunity to do pin that down chronologically, that's distinctive value. If at some level of resolution Io is probably pretty much the same in 2045 as in 1979, then any image is as good as any other, and then maybe the jupitershine imagery adds little. And I'm making it sound like the change is a known quantity, but it's much more complex than that, with stochastic nature and unknowns pertaining to Io, to future missions, to its activity, all challenging and exciting. However it shakes out, hats off to those of you playing a part. People who haven't been born yet will study these images and potentially (this is partly up to Io itself) advance the science with them.

FWIW, the massive ground based telescopes now in the works will provide the potential for regular monitoring of Io's visible changes, subject to geometry, and observational time. Just a pinch of observation time, though, would easily surpass the scarcity of spacecraft missions we have had so far.

[Bjorn Jonsson]

From the PJ57 thread:

Mike, I am definitely coming around to the idea that if you can get well exposed Jupiter-shine images in the green filter, being able to stack them to improve SNR and getting more of them would be fine. While RED has the best SNR, GREEN has the best balance of SNR and albedo information.

A possible drawback is if the PJ56 problem returns at PJ58. If that happens, red images will be much better. So if possible, it might make sense to also take at least one red-filtered Jupitershine image just in case.

[Brian Swift]

From the PJ57 thread:


A possible drawback is if the PJ56 problem returns at PJ58. If that happens, red images will be much better. So if possible, it might make sense to also take at least one red-filtered Jupitershine image just in case.

NOOOOOO. PJ56 problem is not coming back before PJ112.

[mcaplinger]

A possible drawback is if the PJ56 problem returns at PJ58.

Compare the progression of black offset and noise during PJ56 (a lot) with that in PJ57 (practically none). Even if PJ58 proceeds like PJ56 did (which we hope is unlikely) most of the change would happen after the Io encounter.

We hope.

[kymani76]

Map for PJ58 Io flyby from SPK. Ground track covers the distance of +100.000/-100.000 km.

EDIT: fixed night shadow.

[MarcF]

I expect to see some beautiful images of Ra patera, my favorite volcano. Located near the terminator, we should finally have an idea of the topography of this shield volcano. And then, we'll have some incredible views of Loki. I wonder about the topography of this lava lake and especially its surroundings, which looked quite flat in one of Galileo's last images. Fingers crossed.

[mcaplinger]

My initial cut at PJ58 image timing for Io is:

2024-034T17:32:00, two images, high and low TDI, RGB
2024-034T17:39:00, two images, high and low TDI, RGB
2024-034T17:50:00, four images, first high TDI, three low TDI, RGB
2024-034T17:56:00, two images, high and low TDI, RGB

high TDI will be 6, low TDI will be 2.

All image spacing is 60 second. All compression is lossless. I thought about taking one-band images but due to various constraints I couldn't make it work without compromises.

Feel free to provide feedback. But keep in mind that the FOV of Junocam rapidly slides across Io near closest approach, so if I did something that seems odd, I might have done it intentionally.

[kymani76]

I updated the flyby map with new information above.

[mcaplinger]

I updated the flyby map with new information above.

Thanks. But without seeing where the Junocam FOV is along the ground track, it may be hard to understand why I picked the times I did. Visualizing this on a flat map is tough, as I well know. These times were a product of going back and forth in Cosmographia repeatedly, looking at the evolving FOV coverage.

[volcanopele]

A pretty decent set of observations. I might replace the second set with an extra image at the front of the third set (so roughly 2024-034T17:49:00), but I'm not sure how that works for you for bandwidth and data volume. The second set doesn't really add much to the coverage or resolution, and wouldn't be useful for something like the Masubi plume. With high TDI at 2024-034T17:49:00, should provide highest resolution coverage of Io. Covers Masubi, Kanehekili, Shamshu, and Janus. or just take the High TDI image in the second set? The main "Kodak moment" is in the first set anyway.

[mcaplinger]

A pretty decent set of observations. I might replace the second set with an extra image at the front of the third set (so roughly 2024-034T17:49:00), but I'm not sure how that works for you for bandwidth and data volume.

I'll look at it. Keep in mind that all of these times are +/- 15s and I can only take four images in a set before incurring an additional delay. I could start the third set earlier but only at the cost of dropping the last image it currently has, which I was reluctant to do. I tend to not value the nightside images that highly, but maybe that's the wrong bias to have.

[kymani76]

I made another visualisation of the flyby, including Jason's suggestion for 17:49:00.
No attempt was made to account for Juno's distance from Io, attitude or FOV.

[mcaplinger]

No attempt was made to account for Juno's distance from Io, attitude or FOV.

Pretty, but the FOV is rather important. 17:49 just doesn't have much of Io in it.

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