I’m going to try and do several posts explaining some of the lesser known features on Phoenix – that robotic arm is getting too much attention for its own good. Pictured here is one of the color calibration targets that was lurking along the edge of the PIT testbed. A thin disc, a little smaller than a hockey puck, the target serves as a spectroscopic reference point. The stereo imager, for instance, will snap a picture of the target, so that when it then takes a picture of the ruddy landscape, it will know just how red it is. The target designer, Dan Britt, of the University of Central Florida, says one improvement over previous calibration targets is that this one contains magnets that will fend off dust.