High spatial and spectral resolution pictures of the faint galactic H alpha background

Gray-scale maps of the diffuse galactic H alpha emission have been constructed from H alpha scans in a 1 x 1.2 deg grid within a 10 x 12 deg region centered near galactic longitude 144 deg, galactic latitude 21 deg. These maps display the galactic H alpha intensity distribution down to an effective emission measure of 1 - 2 pc/cm to the 6th for a series of seven narrow (12 km/sec) radial-velocity intervals between -76 and +8 km/sec (LSR). The observations reveal that some of the emission originates from long (greater than approximately 10 deg), narrow (less than approximately 1 deg) filamentary structures and from large, diffuse regions that extend in some cases approximately 1 kpc below the galactic plane. Most of these emission features may be accounted for by regions with electron densities of about 0.2/cu cm.