From the "Viking Archive" - Viking 2: a few seconds before Sunrise (1)

"...Early in the mission, when it became clear that there was a large amount of scattering particles in the lower atmosphere, we realized the potentially dramatic appeal of low Sun pictures. However, the first priority was to document the landscape with HR and color images. Following several weeks of successful operation on the Martian Surface we relaxed to the point of attempting exotic but high risk pictures...".