This image of Deimos is composed of four images taken by Viking Orbiter 2 on August 25, 1977 through red, green, violet, and clear filters.
The Viking orbiters are the only spacecraft to have obtained views of anything but Deimos' Mars-facing hemisphere. This is a view up into the enormous crater that dominates the southern hemisphere of Deimos. It is hypothesized that the ejecta from this crater re-accreted onto Deimos, producing its oddly smooth surface. This basin, like all but two of the craters on Deimos' surface, is not named. The image is a red-green-violet composite overlaid on the better-quality clear-filter image and has been enlarged by a factor of two.