Variation of aperture correction from small to large apertures as a function of the image quality, IQ, defined as sigma of a Gaussian fit to the PSF (in pixels). Apertures are scaled with the IQ: small apertures correspond to a radius of 7.5 × IQ and large apertures to a radius of 20 × IQ. The aperture corrections are computed as φ7.5/φ20 − 1 where φ7.5 and φ20 denote instrumental fluxes in the small and large aperture, respectively. Data points correspond to the median of aperture corrections in bins of IQ over all the exposures in the survey. Results for short (and slightly out-of-focus) exposures on Landolt fields (black circles) and long exposures on deep fields (black squares) are displayed separately.
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