LSD Stokes I, V, and diagnostic null N spectra (from bottom to top) of HD 169142. These are calculated using ESPaDOnS (bottom) and HARPSpol (top) observations. The employed line masks and the dates of observations are indicated. The Stokes V and N spectra are magnified by a factor of 30 for better visibility. The rather narrow Zeeman feature identified in the Stokes V spectra as definite detections are highlighted in blue, whereas the broad Zeeman features identified as marginal detections are highlighted in green. The grey bands in the N spectra and the red bands in the Stokes V spectra correspond to a 1σ uncertainty.