Blowup of the region delimited by a dash-dot rectangle in Fig. 4. The angular resolution of these data is given by the filled dot drawn in the upper left-hand corner of the image. The white thin line ellipse represents GS305+04-26. The white boxes mark the location of the pulsars. The star symbol indicates the location of Cen OB1 members identified as such by both Humphreys & McElroy (1984) and Corti & Orellana (in prep.), whilst the unfilled white squares signal the position of those stars considered to be members of Cen OB1 only by Corti & Orellana (in prep.).