Maps of the emission line kinematics of the DIG in IC 1553. Top left: map of the Hα line-of-sight velocity in km s⁻¹ with contours from the continuum map. Top right: map of the Hα FWHM in km s⁻¹ after correcting for LSF broadening with Eq. (2). Bottom row: FWHM maps measured on [S II]λ6717 (left) and [N II]λ6583 (right), LSF-corrected in the same way. The white contours are from the continuum map as before. The violet contours visualize the alignment with the respective emission line flux by separating bins based on the following flux thresholds relative to Hα: [S II]λ6717,6731/Hα ≷ 1.0 (left) and [N II]λ6583/Hα ≷ 0.60 (right).