Example of the 3D projections in the cartesian system for galaxy #1. The blue disk and segment represent the stellar disk and the observed radio tail. The red and black vectors are, respectively, the projections of and . From top to bottom: projection along the LOS (which corresponds to the observed projection), along the E–W axis, and along the N–S axis. In the top panel, we show the θ_V (white, filled) and the θ_tail (white, dashed) angles.