Sol 4900 (!), November 5, 2017. To understand what caused the striations on the target dubbed Mesilla, Opportunity’s science team took advantage of the rover being parked at La Bajada to reshoot the rock with the Microscopic Imager. Once again, it used six frames, but the lighting is different and the framing better. (Earlier view here.) Click image to enlarge it.
Opportunity raw images, its latest mission status, location map, and atmospheric opacity, known as tau.