H I 21 cm spectra at the center beam. In each panel, the gray line is the observed spectrum T_r, the blue line is the recovered T_H I using method 2, and the red line is T_ab. Values of T_ab on the y-axis range from 0 to 20 K for all sources except G174.08-13.2, which uses 0–60 K. The orange and blue squares represent the sources that can and cannot be successfully fit using method 1. The blue line is not shown for spectrum with fit τ smaller than 0.01.