Juno Perijove 22, September 12, 2019 Options

[fredk]

Averaging over the pixels in a large-enough shadow might help. But it sounds like stray light will be the limiting factor.

About the Io-Europa-Ganymede resonance, that should be for the sidereal periods, not solar (synodic). So there's no reason you couldn't have some of those three moons fat crescent or gibbous when Io casts it's shadow on Jupiter. Here's the view during PJ22 from the solar system simulator:

Ganymede was a fat crescent at that time.

It shouldn't be too hard to estimate the level of scattered Ganymede light at that time.

[Kevin Gill]

Fisheye Composite for the Io Shadow

JNCE_2019255_22C00023_V01
JNCE_2019255_22C00024_V01
JNCE_2019255_22C00025_V01
JNCE_2019255_22C00026_V01
JNCE_2019255_22C00027_V01
JNCE_2019255_22C00028_V01

Rendered from the perspective of '28.


Perijove 22 - Io Shadow Composite

[Sean]

Awesome results Kevin!

[JRehling]

Thanks, fredk!

If the HST took a picture of Jupiter while the former was in the Earth's shadow, that would seem to limit stray light profoundly, but trying to limit noise to zero is difficult.

[Brian Swift]

Animation of Io shadow eclipse progressing across Jupiter - https://youtu.be/N5A7fXWMt6k

[Bjorn Jonsson]

An approximately true color/contrast version of PJ22_28 processed to give an idea of what a fairly typical consumer type camera (or even a phone) might have seen if no zoom was used:



North is to the upper left. Here Juno was very close to Jupiter's cloud tops (altitude ~7900 km) and about 12000 km from the center of Io's shadow. Because of this close range it is impossible to capture all of Jupiter's globe in a single image. For that a fisheye type lens would be needed (for a fisheye view see Kevin's image in his post earlier in the thread).

[Kevin Gill]

A wide pole-to-pole map view using PJ22 imagery. Blending and alignment was done largely by hand.


Jupiter - Perijove 22 - Map Composite


And a flyover video on YouTube: https://youtu.be/s8smStabXqg

[Sean]

This is beautiful Kevin! Amazing job!!

[Bjorn Jonsson]

Perijove 22 was not a 'Great Red Spot (GRS) flyby'. Despite this, map-projected images show some details in the GRS' western half (the GRS was on the limb in a few PJ22 images). And the convective area west of the GRS was fairly well imaged during this flyby. This is a map-projected mosaic of PJ22 images 39 to 43 in approximately true color/contrast and enhanced versions:




From this it is clear that the convective area west (or WNW) of the GRS is still active. The appearance of other parts of the South Equatorial Belt (SEB) has recently at least sometimes been as if the SEB was about to fade (turn whitish) but if history is any guide, this shouldn't happen unless the convective activity west of the GRS shuts down.

It's going to be interesting to see what happens here.

[Bjorn Jonsson]

This is an orthographic mosaic of images PJ22_20 and PJ22_21 in approximately true color/contrast and enhanced versions:



The small and very bright cloud below center is located near planetographic latitude 51.6 degrees north and is about 250 km across. The effects of the varying solar illumination across the image have been removed (otherwise the northern half of the image would be darker relative to the southern half than it is here).

Lots of interesting details are visible, including cloud shadows and evidence of vertical relief in the clouds. Many interesting and beautiful small ovals are also visible. Some of these appear to be connected by 'lanes'. An obvious example is the pair of brownish ovals at upper right. North is up in the images.