Footprint of the five SPIRE FTS observations over the SPIRE 250 μm photometric image. White circles show the layout of the unvignetted field of view (FoV ~ 2.0 arcmin in diameter) of the four Must-Do observations, and the white-dashed circle shows the FoV of the pvanhoof observation. The total area coverage by the five observations is ~6 × 8 arcmin². Layout of the FTS detector arrays (SLW in green and SSW in red) and the FoV (black) is shown in the lower-right corner. The circle sizes of the detectors correspond to the FWHM of the beam. Black contours trace levels: 10, 12.5, 15, 17.5, and 20 MJy sr^-1.