Wide-angle images of Mars were laid in place on
a globe already containing an indistinct, earth-based view of Mars.
The Mariner 6 pictures make two horizontal rows above; the Mariner
7 pictures extend from center to bottom right and across the south
polar cap.
The Visual Imaging Investigation (TV experiment) for Mariner
6 and 7 used two cameras on each spacecraft, in order to obtain
both broad coverage and high resolution. Camera A, with a wide-angle
lens, showed large areas of the planet, 1000 x 1000 kilometers
and details as small as 3000 meters during near encounter. Camera
B, with a telephoto lens, showed 100 x 100 kilometer areas and
details as small as 300 meters. The cameras operated alternately,
with each one taking a picture every 84 seconds.