A detail of the Pipe extinction maps. Frame a) shows the 1′ resolution NICER reference map (Lombardi et al. 2006) convolved to 3′ resolution. The other frames show relative differences between: Lombardi et al. NICEST and NICER maps (frame b); both convolved from 1′ to 3′), M1-NICER with the original resolution of 3′ and Lombardi et al. NICER convolved to the same resolution (frame c)), and M1-NICEST with the original resolution of 3′ and Lombardi et al. NICER convolved to the same resolution (frame d)).