Scintillation rate determined through a Gaussian regression analysis (blue points with ±1σ errors); the maximum likelihood model (black curve) is overplotted. The annotated text gives the model parameters and the reduced χ² of the fit. The phase at the vernal equinox is defined to be zero, with phase increasing with time. Magenta crosses show the inverse of the scintillation timescale measured directly from the autocorrelation function (ACF) of the light curves during epochs of sufficiently rapid variations.