MIRI MRS commissioning data of the spatially extended planetary nebula NGC 6543 (the Cat’s Eye Nebula) in the 9.94–11.87 µm range. Top left: detector-level reduced MIRI MRS data. A small region of interest (red box) is selected on a bright emission line. Top right: raw pixel voltage integration ramps of the pixels selected from the left image (solid colored lines). The dashed colored lines are produced from linear fits to the first two frames in each ramp. The horizontal black line at 55 000 DNs shows the saturation value for the MIRI MRS pixels. Bottom: 1D Voigt profile fitted to the estimated emission line flux.