Blue supergiants in the spiral galaxy M 81 at 3.47 Mpc distance. Top: sHR diagram; bottom: classical HR diagram. Spectroscopic data from Kudritzki et al. (2012). Evolutionary tracks from Meynet & Maeder (2003) for Milky Way metallicity and including the effects of rotational mixing are shown (in increasing luminosity) for 12, 15, 20, 25, and 40 solar masses, respectively. The blue supergiant plotted in red is discussed in the text.