also able to display such contrasts however, at the Solar limb with a high viewing angle (e.g. @Unruh1999; @Ahern2000). At the viewing angle of our facula, we would only expect to see a $\sim3\%$ contrast if this were a Solar facula (e.g. @Ahern2000). However, since WASP-52 is a more active and later type star it is possible it could display higher contrast faculae.

Measuring the residual red noise
--------------------------------

In order to measure the systematic red noise in the residuals, we observed how the fractional root mean square (RMS) of the residuals with respect to the flux varied with binning of the data. Fig. \[fig:rms\_vs\_bins\] shows the RMS for a number of different bin sizes. The line overlaid corresponds to pure, Gaussian, white noise with a gradient equal to $1/\sqrt{N}$ where $N$ is the number of points per bin. The factor, $\beta$, quantifies how the actual binning gradient deviates from pure white noise [@Winn2008]. The $\beta$ factors found here show that the residuals do deviate from pure white noise but with amplitudes of only 0.5 mmag.

![The residual RMS scatter once the spot model has been subtracted for NaI (top panel), $g'$ (middle panel) and $u'$ (bottom panel). The error 