Figure 8.

The Mastcam calibration target on board Curiosity as viewed from three different cameras. The target is a flight spare of the MER Pancam calibration target, described by Bell et al. [2003] to which ring‐shaped “sweep” magnets were added to provide dust‐free areas on the color and gray swatches [see Bell et al., 2017]. (a) Details on the target, including initial sand and dust clinging to the embedded ring magnets, are evident in this sol 14 Mastcam‐34 view (from image 014ML0000210000100207E01). (b) The calibration target as viewed from a different camera position by the MSL MAHLI on sol 544 (portion of image 0544MH0003510000201493C00). (c) For comparison with the scale and focus of the view to the right in Figure 8d, this is the Mastcam‐34 view of the calibration target on sol 14 (image 014ML0000210000100207E01). (d) This is the Mastcam‐100 view on the same sol (image 0014MR0000210020100071E01). The target is too close to the Mastcam‐100 camera head for the camera to focus on it; nevertheless, sufficient pixels cover the red and gray swatches so as to be useful for in‐flight calibration [Bell et al., 2017].