... Saturns Moon Tethys . ... It was visited by both Voyager spacecraft - Voyager 1 in November 1980 and by Voyager 2 in August 1981. ... Tethys shows a large impact crater that nearly circles the planet. ... During April and May, attention has been focused on the western evening sky, presenting its spectacle of bright planets and crescent moons shortly after sunset. ... The star that appears to powers the nebula, although young and bright, does not seem hot enough to create some of the colors observed....