Point spread functions of our OmegaCAM data. Top-left panel: inner parts of the Hα PSF. Top-right panel: inner parts of the r-band PSF. Bottom panel: radial profile of the extended Hα PSF (red curves) and r-band PSF (blue curves). The r-band PSF is normalized to its maximum value, and the Hα PSF is normalized so that it has a total flux equal to the r-band PSF. The dot-dashed curves show the fractional cumulative flux outside a given distance from the center. The black vertical lines correspond to the separations between the different parts of the PSFs (2″, 8″, and 100″; see text). The separation between the two middle parts (solid black line at 8″) is also shown in the top panels as a black circle.