Apollo 16 astronaut Charles M. Duke Jr., pilot of the Lunar Module 'Orion', stands near the Rover, Lunar Roving Vehicle (LRV) at Station no. 4, near Stone Mountain, during the second Apollo 16 extravehicular activity (EVA-2) at the Descartes landing site. Light rays from South Ray crater can be seen at upper left. The gnomon, which is used as a photographic reference to establish local vertical Sun angle, scale, and lunar color, is deployed in the center foreground. Note angularity of rocks in the area.