Radio detection of J1304+2938 in the FIRST survey at 1.4 GHz, shown by the coloured map and the associated colour bar. The surface brightness contours at levels of 3, 6, 12, 24, and 48σ from the Apertif imaging survey are superimposed in white, where the rms noise level of the Apertif imaging survey is σ = 40 μJy beam⁻¹. On the lower left, the restoring beams are shown as a red and a white ellipse for the FIRST and the Apertif imaging survey, respectively. A second, resolved source at roughly 40 arcsec is found to the south.