VIS and NISP focal plane arrays. Left panel: VIS FPA, illustrating the detector placement. The dashed line shows the joint FoV of both instruments. Two narrow strips at the extremes of the Y axis are outside the joint FoV. Right panel: NISP FPA, with two narrow strips at the extremes of the X axis outside the FoV (the reference frame is X_FoV − Y_FoV; see also Fig. 2 and the definition at the end of Sect. 2.1).