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With the amazing images coming back from Juno's flyby of Io, I finally took a stab at processing some JunoCam images. This image shows Io's north polar region from 2839km distance.

flic.kr/p/2ppYk8v
Credit: NASA/JPL-Caltech/SwRI/MSSS/Simeon Schmauß

#Io #Jupiter #Juno #Astrodon #Solarocks #Space #Astronomy

Half lit image of the Jupiter Moon Io showing a mostly brownish surface. Sharp mountains stand out against the otherwise smooth surface and cast long shadows along the terminator line. Black lava flows are scattered around on the surface. The shadowed side of the moon is dimly lit by Jupiter and was slightly brightened during processing. Credit: NASA / JPL-Caltech / SwRI / MSSS / Simeon Schmauß

Io - PJ57-23 - approximate true colors - HDR

JNCE_2023364_57C00022_V01 Capture time: 2023-12-30 08:37 UT Height above surface: 2839.6 km Jupiter's innermost moon Io as captured by the JunoCam instrument during Perijove 57.
Flickr
#space #Astronomy #Jupiter #IO #Juno #Astrodon #solarocks

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in reply to Simeon Schmauß

Simeon Schmauß
Simeon Schmauß
• •
I processed this image from the individual framelets, which I preprocessed with a python script and then assembled in PTGui.
This allowed me to retain the complete horizon which is often lost with JunoCam images.
screenshot of PTGui. A source framelet is displayed with control points placed on it for alignment.
the red channel of the Io image in PTGui with red lines indicating the stitching between the individual framelets.
in reply to Simeon Schmauß

Simeon Schmauß
Simeon Schmauß
• •

I also developed a color calibration for the JunoCam filters based on the CIE1931 color system. This allowed me to process the image in approximate true colors as the human eye would see them.

However, this wasn't an easy task because the JunoCam RGB filters don't match the spectral response of the human eye very well. Particularly the red filter is way too sensitive in the near infrared and Io's surface is especially reflective there.

line plot comparing the CIE1931 color matching functions, with the JunoCam RGB filters. The CIE curves are smooth gaussian distributions, while the JunoCam filters have very sharp edges and don't match the shape of the CIE curves. An ideal color camera would have sensitivity curves very similar to the CIE curves to allow it to produce accurate colors.
in reply to Simeon Schmauß

Simeon Schmauß
Simeon Schmauß
• •

In addition to the common ColorChecker 24 spectral target I used an Io reflectance spectrum (Spencer et. al. 1995), so I could better fit my calibration matrix to the spectral characteristics of Io.

Even with weighting the Io spectrum, my calibration only managed a dE of the Io reference target of 8.3 which really isn't great. That's why I'm only calling it an "approximate" true color image for now.
There is probably room for improvement by using more representative spectra.

color calibration report from DCamProf. The reference Jupiter and Io spectral target are at the bottom.
in reply to Simeon Schmauß

Simeon Schmauß
Simeon Schmauß
• •
Even with those compromises my image still looks rather similar to
@volcanopele's Galileo true color processing of Io.
I might try to process/calibrate some Galileo and Voyager images in the future.
planetary.org/articles/2629

Exposing Io's true colors

Thanks to its active volcanic activity and sulfur-rich surface, Io is one of the most colorful worlds yet seen in the Solar System, save the Earth of course
The Planetary Society
@volcanopele
in reply to Simeon Schmauß

Tom Montgomery
Tom Montgomery
• •
Not a very hospitable place to visit! 😬
in reply to Tom Montgomery

Simeon Schmauß
Simeon Schmauß
• •
@tom30519 Not at all, but I would give everything to see it with my own eyes from orbit (in a very radiation hardened spacecraft that is) 😁
@Tom Montgomery
in reply to Simeon Schmauß

Tom Montgomery
Tom Montgomery
• •

With currently available transportation, the trip there is about 5 years, and, presumably another 5 to come back to Earth! 🚀

I think I'll be content with the amazing images that Juno is providing! 😃

in reply to Simeon Schmauß

Wöhnlich
Wöhnlich
• •
what are the red in the upper right part of the image? Looks like wind spread it in lines? Oh oh and what is the orange/yellow ring in the lower right part?
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