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tokens: al. 2014 ). BRITE-Constellation obtained observations of the Cygnus-II field from June 1 to November 25, 2015. The star 43 Cygni was observed for only 13 days with BRITE-Lem (BLb) in the blue filter and for 156 days with BRITE-Toronto (BTr) in the red filter, both in chopping mode, where the position of the target star within the CCD plane is constantly alternated between two positions about 20 pixels apart on the CCD. This procedure was adopted to mitigate the impact of high dark current in CCDs. A detailed description of this technique is given in Popowicz et al. (2017) . As the blue data set from BLb did not have sufficient quality for an asteroseismic analysis, we omitted it from our further investigation. Fig. 1 Complete BRITE-Toronto light curve of 43 Cygni ( top ) and zoom into a 20-day subset ( bottom ). The BRITE-Constellation data of 43 Cyg were corrected for instrumental effects according to the iterative procedure described by Pigulski et al. (2016) . This procedure was, however, modified to include two-dimensional decorrelations. Since 43 Cyg shows variability with large amplitude, decorrelations were made using residuals from a fit consisting of a sum of sinusoidal terms. For 43 Cyg, the model consisted of five terms: four modes with frequencies 1.250 d, 1.288 d, 0.963 d, and 1.516 d, plus a combination frequency (1.250 d0.963 d = 0.287 d). This model was used for all BTr setups. The fit was recalculated at each step of the decorrelation. The whole procedure included outlier rejection, 1D and 2D decorrelations, and removal of corrupted orbits (e.g. affected by poor stability of the satellite). Decorrelations, both 1D and 2D, were made using parameters provided in Data Release 3 (see Popowicz et al. 2017 , or the BRITE Public Data Archive 2 for the explanation of parameters) and a given satellite orbital phase as an additional parameter. The decorrelation was made sequentially, allowing for multiple decorrelations with the same parameter (or a pair of parameters). At each step, the parameter showing the strongest correlation was chosen for correction. The strength of a correlation was defined as the degree of reduction in variance due to decorrelation with a given parameter (for 1D) or a pair of parameters (for 2D). The iterations were stopped when all correlations (both 1D and 2D) resulted in a variance reduction smaller than 0.05 per cent. The whole procedure was run independently for each setup. Outliers and the worst orbits were rejected at least twice during the whole procedure. After decorrelating the data, the blue and red data were separately combined, taking the mean magnitude offsets between the setups into account. The complete BTr light curve of 43 Cygni consists of 98 481 data points and is shown in the top panel of Fig. 1 , while the bottom panel shows a zoom into a 20-day subset. 2.2. HERMES spectra We obtained ten high-resolution spectra with high signal-to-noise ratio (S/N) for 43 Cygni using the HERMES