Variation of the passbands’ cut-on (left) and cut-off (right) wavelengths with field position. The grey squares in the background mark the 4×4 detector grid, with the SCA positions shown in yellow. The white square shows the centre of the FOV, with its applicable passband wavelengths listed in Table 1. Note: This is the view from the sky towards the FPA, see Fig. A.1 for FPA coordinate system details.