Juno perijove 4, February 2, 2017 Options

[Gerald]

It's time to open a perijove-4 thread.
Voting is open for another two days. So, don't hesitate too long.
Besides the discussion and the POIs on the mission page, you might consider John Roger's detailed discussion of several interesting features.

If everything goes well, all instruments will be switched on.

[Bjorn Jonsson]

The JunoCam images are in a word awesome. They are a lot more challenging to process properly than e.g. the Voyager, Galileo and Cassini images but the resulting processed images are every bit as spectacular as the images from the earlier spacecraft that imaged Jupiter. In particular the color is much better than in the Voyager data for obvious reasons.

Here are a few images processed from the image 106 raw framelets. This is the "POI: Oval BA" observation. In the three images below the effects of global illumination have been removed. The contrast and color has been exaggerated and small scale features sharpened to better reveal various features and color variations.




These images show an enormous amount of small scale details. Cloud shadows and vertical relief are clearly visible at many locations. These JunoCam images shows these features better than the best and highest resolution Voyager images do.

The fairly big oval visible in these images is one of the "string of pearls" ovals near latitude 40 degrees south; this is oval A1.

And here is a different version of these images with approximately true color and contrast. Small scale features have been sharpened slightly:



All of these images were produced by using viewing geometry information from SPICE kernels to reproject the raw framelets to a simple cylindrical map. For best results I had to make corrections to the camera pointing. I then used a 3D renderer to render perspective views of an oblate spheroid using the spacecraft's location and the camera pointing at three different points in time when JunoCam was acquiring the original framelets.

Since JunoCam has a very wide field of view (58°) these images should give a fairly good idea of what a naked eye view from Juno's location would look like. This is different from the Voyager/Galileo/Cassini images where the field of view is less than 0.5°. The images from these spacecraft are therefore more similar to what one would see through a small astronomical telescope from a distance of a few million km from Jupiter.

Juno's altitude above Jupiter was only ~14,500 km when the original images were obtained. Therefore the area covered by the images isn't particularly big. Below is a quick and dirty context view. It is based on John Rogers' PJ4 predictive map that can be seen here: https://www.britastro.org/node/8908



And finally an animation showing all of image 106. It's created using Juno's location and JunoCams' pointing when it was imaging Jupiter:
https://vimeo.com/209958488

[JRehling]

Amazing, Bjorn, and wonderful. The white ovals are fascinating – a target worthy of your skills.