Spectra along the slit around the scan step 21 (top panel), step 37 (second panel), step 53 (third panel), and step 66 (bottom panel). The scan step of each cut along the slit is given at the lower left of each panel, increasing from left to right and from bottom up. The y-axis gives the distance along the cut, the limb is thus located at varying positions. The vertical white line denotes the rest wavelength of Ca ii H.