Direct comparison of the spectra of Betelgeuse (HD 39801, top panel) and HD 219134 (middle panel) from the libraries of Rayner et al. (2009, solid lines) and Cenarro et al. (2001a, 2002, dotted lines). In the bottom panel the continuum normalized spectra of HD 219134 are shown. In each panel the difference of the two corresponding spectra are plotted (shifted by +0.4 for displaying purposes) and the rms value is given.