Continuum limb darkening near the FeI line at 6173 Å. Results are shown both as a function of the fractional solar radius r (on the top axis) and (on the bottom axis). Red: From the simulations shown in Fig. 1, including a number of additional angles. Black: An estimate from the HMI instrument. Green: An estimate from Pereira et al. (2013) courtesy of R. Trampedach. Vertical dotted lines indicate 1.0, 2.0, and 5.0 pixels from the limb. The results were not corrected for the PSF of the HMI instrument.