Hα+[NII] emission velocity-colored (left) and intensity (right) position–position–velocity (PPV) diagrams of FH Ser. The top row shows the projection along the observer’s point of view (i.e., the direct image), and the middle and bottom rows show the δ − λ and α − λ projections from the plane of the sky along the east-west and north-south directions, respectively. Information on the LSR radial velocity of Hα is provided by the rainbow color-code shown in the top left panel, with the color span covering the Hα and [N II] λ6584 emission lines of FH Ser. The color-code of the right panels corresponds to normalized flux.