Figure 1
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This false-color scene from the panoramic camera (Pancam) on NASA's Mars Exploration Rover Opportunity documents movement of dust as a regional dust storm approached the rover's location on Feb. 24, 2017, during the 4,653rd Martian day, or sol, of the rover's work on Mars.

Key to detecting the movement is that Pancam color images are combinations of different images taken a short time apart through different color filters. Note that along the horizon, the left portion of the image has a bluish band (with label and arrow in Figure 1). The component image admitting blue light was taken about 150 seconds after the component image admitting red light. A layer of dust-carrying wind hadn't reached this location by the earlier exposure, but had by the later one. A clearer example of this color clue to changing location can be compared at PIA12121, a 2009 view of a dust devil from the Pancam on NASA's Mars Exploration Rover Spirit.

This Sol 4653 Opportunity view is toward the north from the rover's location on the western rim of Endeavour Crater in the Meridiani Planum region of Mars.

JPL manages the Mars Exploration Rover Project for NASA's Science Mission Directorate in Washington. For more information about Spirit and Opportunity, visit http://marsrovers.jpl.nasa.gov.