A unique view of Saturn in the ultraviolet from Hubble captures both of its aurorae in simultaneous glow. The image was captured by the Advanced Camera for Surveys in early 2009, as Saturn was nearing its equinox, so the rings are seen nearly edge-on and their shadow forms a thin black line across Saturn's disk. The aurorae are revealed through the use of a filter that permits only far-ultraviolet light to reach the ACS camera detector. (The blue color is false colorization, as seems traditional for ultraviolet images.)
NASA / ESA / Jonathan Nichols
Saturn’s aurorae with Titan
In this photo, Titan is also entering the view, and casts a shadow on the northern aurora.