Statistical analysis of the limb bins: (Top) Brightness significance I_bin/σ_bin of the limb bin with the highest value for each visit (blue squares). For visit 3, the orange square shows the value when assuming the disk position from Roth et al. (2014b). (Bottom) Histogram of the frequency of limb bin brightnesses for all 414 bins from all visits. The dotted red line shows the theoretical Gaussian distribution for sample size N=414. The dotted blue lines shows a Gaussian distribution fitted to the histogram. The values for max amplitude, A, mean, μ, and standard deviation, σ, are given for both Gaussians.