Voyager 2 Saturn Revisited, Still a lot to be processed and reprocessed Options

[Bjorn Jonsson]

Emily recently mentioned in her blog the availability of calibrated and geometrically corrected Voyager images. Actually I had 'discovered' this dataset several months earlier but then managed to completely forget about it. Now I decided to do something so I downloaded volume 37 and decided to do some quick-and-dirty processing, mainly to check if it was feasible to do a very high resolution map (probably 25 degrees/pixel to match my Cassini map of the southern hemisphere) of Saturn's entire northern hemisphere by colorizing green filtered images using lower resolution color data I processed several years ago - at the resolution I want only green filtered images are available.

This was successful, opening the door to a new 'monster project': A very high resolution full color map of Saturn's entire northern hemisphere.

First a color composite made from wide angle orange, green and blue images:

This one was made from images C4386547_GEOMED.IMG, C4386554_GEOMED.IMG and C4386608_GEOMED.IMG. I adjusted the color to something more realistic than I initially got and removed some reseau marks in Photoshop that were visible, especially near ring edges and Saturn's limb. Some color fringing was also visible on Saturn's disk due to Saturn's rotation while the three images were obtained; I removed this by cloning the color of adjacent areas. The spokes in the rings presented similar problems.

I then colorized a green filtered image obtained at a similar time as the wide angle images above. This was the result:

The image should be fairly realistic and I was happy with the result, especially because I didn't do this very carefully - something better should be possible.

Finally the same image sharpened with an unsharp mask:

Lots of small scale details are visible, especially near the pole.

I will probably post several additional Voyager Saturn images in the next several weeks. As previously mentioned, the plan now is to do a very high resolution map of Saturn's entire northern hemisphere based on these calibrated and rectified images. This means reprojecting the images to simple cylindrical projection. To do this I need to know the viewing geometry. Does anyone know if this information is available somewhere (or if not, if it's likely to ever become available)? I have some SPICE kernels which give me Voyager 2's location relative to Saturn. These are probably fairly accurate. However, the limited instrument pointing information I have is very inaccurate so it's useless to me. I can reverse engineer the viewing geometry/pointing but it's a lot of extra work.

[Astroboy]

Here's something kind of simple... the Saturn rotation approach movie in a version that's totally raw and another that's processed and stabilized. It plays at a rate of 48 minutes per second, or about ten frames per second - I accounted for a 4.8 minute break by doubling the frame prior to the break. I roughly stabilized the whole sequence manually, frame by frame. I could've found a way to do it automatically but it wouldn't have been as satisfying. Manually stabilizing Voyager image sequences is a really relaxing, stress relieving activity for me.

https://www.youtube.com/watch?v=lqibI7-KUAw

It's kind of hard to see due to the erased reseaus and the fact that Saturn is hazy, but a few storms can be seen rotating around the planet. The famous spokes and a ton of moons are clearly visible. Keep an eye out for the occultations and transits!

[Brian Burns]

This is really cool - it's great to see all the orbiting moons.

I haven't tried any automation on the Saturn images yet so don't know how well it will handle the rings - it might not work very well...