This image of Neptune's south polar region was obtained by the NASA Voyager narrow-angle camera on Aug. 23, 1989, when it was at a distance of 25 million kilometers (1.6 million miles). The smallest cloud features are 45 kilometers (28 miles) in diameter. The image shows the discovery of shadows in Neptune's atmosphere, shadows cast onto a deep cloud bank by small elevated clouds. Located at about 68 degrees south latitude, they are the first cloud shadows ever seen by the Voyager on any planet. The dark regions adjacent to the small bright clouds are believed to be shadows, because they are on the side of the cloud that is opposite to the incoming sunlight and because they lengthen in places where the sun lies closer to the horizon. Estimates of the height of these discrete clouds above the underlying cloud bank can be obtained by careful analysis of this data. The Voyager Mission is conducted by JPL for NASA's Office of Space Science and Applications.