Björn Jónsson • Sep 14, 2016
A deep dive into the highest-resolution Voyager Jupiter data
A few weeks before the first Juno high-resolution imaging, I decided to take a look at Voyager color images at various resolutions, with particular attention to high-resolution mosaics. The idea was to get at least some idea of what might be expected from Juno. This resulted in several mosaics, which I will show in order of their resolution, starting with the lowest resolution mosaic.
With the exception of one mosaic (the white oval mosaic), the source images are in all cases green- and violet-filtered images. Most of the hi-res Voyager color observations were performed using this filter combination. This is not optimal for constructing true-color images, but I think I managed to get reasonably realistic color. Here is a quick and dirty global image I used as a test -- the two source images are orange and violet filtered.
Not bad, but I suspect the color could be improved a bit. The color processing I used for the hi-res mosaics is comparable to what I did in this global view. The features shown in the mosaics are semi-randomly selected -- I simply selected images where mosaics could be constructed, color was available and the images looked interesting in some way.
I processed the color of each mosaic in two ways, making one version with approximately true color/contrast version and another where the color and contrast has been exaggerated and the image sharpened to better show various details. Some of the images below are shown in both versions; for both versions of all images, visit this forum thread. The contrast stretch varies for the different mosaics and depends on things like scene brightness and contrast. North is up in all cases. The mosaics are 10-15% bigger than the original data, i.e. they are slightly oversampled to avoid losing details. In all cases the indicated resolution applies to the original data. As usual I reprojected the images to simple cylindrical projection, did all of the mosaicking and color processing there and then rendered an image using the viewing geometry close to the mid-time of the mosaic's imaging sequence.