Physical characteristics So far the only close-up images of Umbriel are from the Voyager NUMBER@1 probe , which made observations of the moon during its MISC@1 flyby in January NUMBER@2 .

Physical characteristics So far the only close-up images of Umbriel are from the Voyager NUMBER@1 probe , which made observations of the moon during its MISC@1 flyby in January , NUMBER@2 .
