Neptune and the "Great Dark Spot"

Caption NASA originale:"This photo was taken by Voyager 2's wide-angle camera. Light at methane wavelengths is mostly absorbed in the deeper atmosphere. The bright, white feature is a high-altitude cloud just south of the Great Dark Spot. Other, smaller clouds associated with the Great Dark Spot are white, and are also at high altitudes.
The Voyager Mission was conducted by JPL for NASA's Office of Space Science and Applications".