Comparison of the real part of the uv visibilities between R Leo Band 4 observations taken on 2017-09-30 (black solid line and circles) and 2017-10-13 (red dashed line and squares). In most cases the error bars are less than the symbol size. The lines represent the uniform disc model, where the long-dashed blue line corresponds to the best-fit model of the 2017-10-13 observations scaled to the flux density of the 2017-09-30 observations. Although the difference in flux density is most likely predominantly caused by the uncertainty in absolute flux calibration, the long-dashed blue line shows that the change in radius of the model is robustly determined.