In January and March 2009, Hubble took advantage of a rare opportunity to record Saturn when its rings are edge-on, resulting in a unique movie featuring both of the giant planet's poles. Saturn is only in this position every 15 years and this favourable orientation has allowed a sustained study of Saturn's almost symmetric northern and southern lights. At the same time Saturn was approaching its equinox so both poles were equally illuminated by the Sun's rays.

These recent observations have allowed researchers to monitor the behaviour of both Saturn's poles in the same shot over a sustained period of time and to study the planet's northern and southern aurorae simultaneously. Given the rarity of such an event, this new footage will likely be the last and best equinox movie that Hubble captures of our planetary neighbour. Besides the double aurora show, the movie also features an added bonus, as some of Saturn's moons, or satellites, are seen passing the disc of their parent planet.

credit: NASA, ESA and Jonathan Nichols (University of Leicester)

source: http://www.spacetelescope.org/videos/html/heic1003b.html