Comparison of GBT and 30′′ VLA data. Top panel: pV slice through centers of the cloud and 8 kpc filament. Position and orientation of the slice is indicated in Fig. 4. The thickness of the slice through the VLA data is 100′′; the thickness of the slice through the GBT data is one GBT beam. The gray-scale shows the VLA data with (2.5,5) × 10¹⁸ cm^-2 contours overplotted in dark-gray. The black contours show the GBT data at (5,10,25,50,100)σ, where σ corresponds to 3 × 10¹⁷ cm^-2. The cloud is detected at the > 10σ level. The thick, red contour shows the VLA data smoothed to the GBT resolution at the 5 × 10¹⁷ cm^-2 level. The emission detected by the GBT is clearly more extended. The VLA contours and gray-scales are not corrected for primary beam effects. The hatched area at the top indicates velocities affected by Galactic emission. The cloud and 8 kpc filament are indicated by arrows. The two horizontal lines indicate the velocities of the channel maps shown in the bottom panels. Bottom panels: channel maps at v = 135.1 km s^-1 (left) and v = 124.8 km s^-1 (right). In both panels the gray-scale shows the VLA data at 60′′. Thin dark-gray contours show VLA column density levels at (1,5) × 10¹⁸ cm^-2. Thin white contours show VLA column density levels at (25,50,250) × 10¹⁸ cm^-2. The lowest contour of 1 × 10¹⁸ cm^-2 corresponds to ~ 2.5σ. Features in the extreme top-right and bottom-left of the channel maps are deconvolution artifacts. The thick black contours show GBT column density levels and are the same as in Fig. 5. The GBT beam and the 60′′ VLA beam are shown in the bottom-left corner of the left channel map.