Astronomy & Astrophysics

Table 1: Comparative photometry relative to the star S1. Relative photometric uncertainties in the last significant digit are listed in parentheses after their respective values. The last column gives the reduced $\chi ^2$ of the fit to a constant flux value. Seeing corresponds to the full width at half-maximum of point sources in the image. The data were obtained with DFOSC on the Danish 1.5 m telescope except that marked with a $\dagger$ , where StanCam on the NOT was used.