TESS target pixel file image of GJ 3090 in Sectors 2, 3, and 29 (created with tpfplotter, Aller et al. 2020). The electron counts are colour-coded. The pixels highlighted in red are used for the simple aperture photometry. The positions of the stars in the Gaia DR2 (Gaia Collaboration et al. 2018) are indicated with red circles (and labelled with numbers according to the distance to the main target in the aperture labelled “1”), their size is proportional to the Gaia DR2 magnitudes.