OFFICE OF PUBLIC INFORMATION
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CA  91109. TELEPHONE (818)354-5011

PHOTO CAPTION
Viking 2-1
P-17442
August 7, 1976

This crescent phase picture of Mars was taken by Viking 2 on
August 5 from a distance of about 400,000 kilometers (250,000
miles) as it was approaching the planet for its orbit insertion 
maneuver.  Viking 2 went into orbit around the planet
at 5:30 A.M., PDT today.  The view is of the morning side.
Toward the top of the picture, the four dark spots are the
huge volcanoes of the Tharsis region.  They appear dark
partly because clouds and haze cover this region at this
time of day, and the volcanoes stand higher than the clouds.
In the bottom part of the picture, at the tip of the crescent, is 
a bright circular feature, the large impact basin,
Argyre.  This basin shows up brightly because its floor is
covered with frost.

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