The Ultra Violet Imager (UVI) on the Swedish Viking Satellite was designed to provide real-time monitoring of the auroral distribution from space. The instrument contains two camera systems each incorporating reflecting optics, a filter, and an open-photocathode image intensifier coupled by fiber optics to a CCD array detector. Under program control a portion of the great circle swept out by the cameras is digitized and transferred into onboard memory. Each image corresponds to an exposure time of approximately one second and all portions of the image are exposed simultaneously providing for the first time unambiguous comparisons between widely separated regions of the auroral distribution. The cameras have been operated in a real-time mode whereby various selectable parameters can be changed, and the first image of the new format can be inspected by scientists within 3 minutes. The significance of obtaining 20-s time resolution between images and measuring the aurora under conditions of full sunlight is demonstrated.