[X] My Assistant

[Bjorn Jonsson]

Juno's perijove 5 is coming up less than two weeks from now - it's on March 27, 2017.

The target selection voting has started and is open until almost four days from now: https://www.missionjuno.swri.edu/junocam/voting?current

A large part of the data volume will be reserved for polar time lapse sequences though.

John Rogers has written a helpful summary of the upcoming perijove 5: https://www.britastro.org/node/9377

[Gerald]

For completeness, here the statistics resulting from the calibration run:

There are peaks and discontinuities near the change of the s/c spin axis.

But at least the camera's optical axis shouldn't change during these maneuvers, with the x-position near 812. The inconsistencies indicate residual flaws in the model, and help to uncover them.

[Bjorn Jonsson]

For completeness, here the statistics resulting from the calibration run:

Have you checked how accurate the interframe delay in the metadata is? For the PJ5 images it is 0.371 but I'm starting to suspect that I might get slightly better results by adjusting it slightly. I haven't tried it yet though but I'm pretty sure any adjustment (if needed) is less than 0.001.

Is it possible to discern any rotation in these large storms within the five and a half minutes between images #109 and #110?
My best candidate is the large white (anticyclonic) oval A6:

Quick back of the envelope calculations seem to suggest this *might* be possible. The elapsed time between the images is ~330 seconds. Assuming a wind speed of ~60 m/s near the A6 spot's periphery (a very crude but probably not bad assumption made by scaling down the speed in the bigger white oval BC in the Voyager era by a factor of ~2 since A6 is smaller) results in a ~20 km movement. This corresponds to roughly 2-3 pixels in the higher-res image which is noticeable if the images are well aligned.

That has some super detail in it, including what look like convective cloud elements. Do we know what the pixel resolution is? Considering the context, these convective clouds on the right are in a zone, with overall low altitude clouds, so that we see more into a water rich level. The redder clouds on the left are in a higher belt. It seems the bluer nature of the zone would be consistent with looking through some overlying clear air with attendant Rayleigh scattering.

Hmmm... but I have always been under the impression that the whitish zones are higher in the atmosphere than the darker and more reddish/brownish belts and that they are probably ammonia cirrus (the water clouds are much lower in the atmosphere and look darker and more fuzzy). But the possible convective clouds in Roman's image are very interesting. An interesting fact is that these small, whitish clouds are very common and not just in Roman's image. They occur both as isolated features, e.g. at ~(435,740) and in 'clusters', e.g. at ~(980,105) in Roman's image above. And there's a lot of them in the whitish zone. Some of them look like cumulus to me. These clouds seem to occur at various locations although some areas are more likely to have them than others.

There are also small/narrow 'elongated', whitish clouds at various locations, typically above darker clouds. I suspect their altitude is similar to the convective/cumulus clouds. Here is an example, an enhanced crop from an image (PJ5 image 110) I'm working on:

[mcaplinger]

Have you checked how accurate the interframe delay in the metadata is? For the PJ5 images it is 0.371...

The metadata value is 1 millisecond too small (there was an off-by-one misunderstanding about how the hardware interpreted the commanded interframe value.) Otherwise it's under the control of a fairly stable crystal oscillator but there could be some drift on order of 10-20 PPM over temperature.

The spacecraft spin rate is usually not precisely 2.000 RPM so that's probably a bigger unknown.