Juno Perijove 48, January 22, 2023 Options

[mcaplinger]

https://www.nasa.gov/feature/jpl/nasa-s-jun...lyby-of-jupiter

The JunoCam imager aboard NASA’s Juno spacecraft did not acquire all planned images during the orbiter’s most recent flyby of Jupiter on Jan. 22. Data received from the spacecraft indicates that the camera experienced an issue similar to one that occurred on its previous close pass of the gas giant last month, when the team saw an anomalous temperature rise after the camera was powered on in preparation for the flyby.

However, on this new occasion the issue persisted for a longer period of time (23 hours compared to 36 minutes during the December close pass), leaving the first 214 JunoCam images planned for the flyby unusable. As with the previous occurrence, once the anomaly that caused the temperature rise cleared, the camera returned to normal operation and the remaining 44 images were of good quality and usable.

The good images have been posted to missionjuno.

[Gerald]

In the meanwhile, I've done some quantitative analysis.

The below PDF contains relative white-balancing linear radiometric factors for Jupiter from PJ43 to PJ48 for r(ed), g(reen), b(lue), together with the quotients PJ n / PJ n-1 for red (quot_r) and blue (quot_b), and quot_r/quot_b for the factor by which the white-balancing linear radiometric factors for the red and blue channel change from one PJ to the next, in the last column quot_br.
Added are plots of time series of columns r, b, and quot_br.
 wb_weights.pdf ( 34.21K ) Number of downloads: 113

I've actually used RGB images with the most frequent TDI setting within the respective PJ for the calibration. Except for PJ48, I removed images with eclipses, or when the GRS was prominent.

This animated GIF visualized the empirically retrieved reddening from PJ47 to PJ48:


You may be right, Björn, that the radiometric factors could change between inbound and outbound images. Juno is indeed crossing some harsh radiation belts.
However, I didn't yet try to find regression curves for the radiometric factors within a PJ.

[mcaplinger]

You may be right, Björn, that the radiometric factors could change between inbound and outbound images.

I don't think he was saying that, I think he was saying that Jupiter is a different color between hemispheres. But even if he wasn't saying that, you can't prove otherwise.

Not to complain, but when people here say stuff about radiation changes, someone from the project stumbles across it, and I end up having to do more work to try to quantify it. So far I haven't found unequivocal evidence that there have been intrinsic instrument changes. You could do me a favor by being as specific as possible about what you are doing, which images and which regions of which images, attempts to control for photometric effects if any, etc. Then I can just paste that into my slides, and I'll be happy to give you all the credit.

[Gerald]

Not to complain, but when people here say stuff about radiation changes, someone from the project stumbles across it, and I end up having to do more work to try to quantify it. So far I haven't found unequivocal evidence that there have been intrinsic instrument changes. You could do me a favor by being as specific as possible about what you are doing, which images and which regions of which images, attempts to control for photometric effects if any, etc. Then I can just paste that into my slides, and I'll be happy to give you all the credit.

Give me a day or so to compile all the underlying data I've more or less readily available. I'll mail you a download link with a cc to at least two other members of the Juno science team. We've already discussed this topic in person before. I'm ready to take over whatever extra work load is required to the degree I'm authorized.