Jupiter and Ganymede in Near-UV and Blue
A new Jupiter to add to the Hubble Jupiter collection, this time in near-ultraviolet and visible blue light. Note this is not far enough into ultraviolet to view the auroras, just in case you were wondering. The Great Red Spot is just coming into view as the planet and its bands rotate about its axis. However, at these wavelengths, it is quite dark, and appears blue with this processing. Red Spot Junior is also prominently visible as another dark blue spot.
Of particular interest to me, and why I chose this dataset, was the presence of Ganymede within the frame, floating at top left in front of Jupiter. I did not know what Ganymede looked like in near-ultraviolet, but apparently now I do. I wasn't sure what to expect, but the leading and trailing side of the moon are quite different in near-ultraviolet compared to how they are in visible light. The trailing side is a bit darker, and the leading side a bit lighter, which is why Ganymede appears to have this fascinating red gradient over it. I don't know why this is; all I know is that I didn't force it to be that way, and it's not a mistake.
This image represents Jupiter and Ganymede as they would have appeared on 2017-02-02 at 12:16 UTC.
This was another image of Jupiter captured jointly with the Juno craft. See the following proposal:
Red: WFC3/UVIS F343N (id9o23xyq)
Green: WFC3/UVIS F275W (id9o23xzq)
Blue: WFC3/UVIS F225W (id9o23y0q)