Top: the raw BAb light curve of β Cen. Middle: raw magnitudes plotted as a function of x_cen (left) and y_cen (right). Vertical dashed lines encompass the ranges of x_cen and y_cen in which the raster fully includes the optimal aperture. Bottom: the BAb light curve of β Cen after removing data points that come from frames with aperture extending beyond the raster edge.