The population in the background of open clusters: tracer of the Norma-Cygnus arm

We present colour-magnitude diagrams of open clusters, located in the range 112 degrees < l < 252 degrees, manifesting stellar populations in the background of clusters. Some of the populations are found to be located beyond the Perseus arm and may be the part of the Norma-Cygnus (outer) arm. The outer arm seems to be continued from l similar to 120 degrees to similar to 235 degrees. The background populations follow the downward warp of the Galactic plane around l similar to 240 degrees.