History of Hubble Space Telescope (HST)

This is the first image of Saturn's ultraviolet aurora taken by the Space Telescope Imaging Spectrograph (STIS) on board the Hubble Space Telescope (HST) in October 1998, when Saturn was a distance of 810 million miles (1.3 billion kilometers) from Earth. The new instrument, used as a camera, provides more than 10 times the sensitivity of the previous HST instruments in the ultraviolet. STIS images reveal exquisite detail never before seen in the spectacular auroral curtains of light that encircle Saturn's north and south poles which rise more than a thousand miles above the cloud tops. Saturn's auroral displays are caused by an energetic wind from the Sun that sweeps over the planet, much like the Earth's aurora that is occasionally seen in the nighttime sky. Unlike the Earth, Saturn's aurora is only seen in ultraviolet light that is invisible from the Earth's surface, hence can only be observed from space.