Part of the field of view around PG 1115+080, as seen with the ESO MPIA 2.2 m telescope at La Silla Observatory. The field is a stack of 92 exposures with seeing <1.1″ and ellipticity <0.12, for a total of ~8.5 h of exposure. The stars used for the modeling of the PSF are labeled PSF 1 to PSF 6, in red, and the stars used for the exposure to exposure normalization are labeled N1 to N6, in green. The insert shows a single, 330-second exposure of the lens.