Comparison of the results for star HD 37394 using BGLST, GLS-T, and GLS models with constant noise variance in the plots in the left column and intra-seasonal noise variance in the right column. Panels a and b: data (black crosses), BGLST model (red curve), GLST-T model with trend added back (blue dashed curve), GLS model (green dash-dotted curve), the trend component of BGLST model (red line), and the empirical trend (blue dashed line) are shown. Panels c and d: spectra of the models with same colours. The dashed lines indicate the locations of the corresponding maxima.