Description of the problem

An overview of the situation was given in section 2.3. Column 24 of the LW detector is offset from the centre of the array by 8 pixels in the +M direction for an unconstrained raster (i.e. in the direction of the spacecraft Z axis.) Unless the observation date is known or the raster orientation is constrained, the orientation of the column on the sky is not known.
The observer will need to compensate for the missing column if he or she:

• has a single pointing observation of an extended source or is looking for faint point sources in a field.
  
• is observing a point source and the PSF spills flux into the missing column. (e.g. 1.5" pfov).
  
• is making a large raster with step sizes larger than 22 pixels, so that the region of sky corresponding to the missing column is not later mapped onto a good portion of the array and need good data for the entire region.