Could Ganymede's aurora be seen with the naked eye? If one was orbiting in the Jovian system, as depicted in this artist conception,



could the aurora be seen unassisted? 

Hubblesite-Illustration Credit: NASA, ESA, and G. Bacon (STScI)
The aurora depicted in the artist's conception is of ultraviolet light.  It would not be seen with the naked eye.

"NASA's Hubble Space Telescope observed a pair of auroral belts encircling the Jovian moon Ganymede. The belts were observed in ultraviolet light by the Space Telescope Imaging Spectrograph and are colored blue in this illustration. They are overlaid on a visible-light image of Ganymede taken by NASA's Galileo orbiter. The locations of the glowing aurorae are determined by the moon's magnetic field, and therefore provide a probe of the moon's interior, where the magnetic field is generated. The amount of rocking of the magnetic field, caused by its interaction with Jupiter's own immense magnetosphere, provides evidence that the moon has a subsurface ocean of saline water."