Comparison between HAGRID generated flux levels and the calibrated map of Finkbeiner (2003). Top: map of HAGRID-selected positions in the Cygnus-X region of the northern Galactic plane. Every selected position has been coloured according to the logarithm of the estimated surface brightness (in ergs cm⁻² s⁻¹ arcsec⁻²). White areas will have log(surface brightness) <  − 15.5. The region shown spans 50 sq. deg., or 3.6% of the total area processed, and contains 20% of the identified candidate target positions. It is the most line emission-rich part of the northern plane. Bottom: same area in the Finkbeiner (2003) Hα map, with 6 arcmin pixels. The data available in this region are a combination of images from VTSS (circular footprint) and WHAM (making up the much coarser resolution background).