TITLE: GCN CIRCULAR NUMBER: 18612 SUBJECT: GRB 151118A: Optical observations from OSN DATE: 15/11/18 04:36:51 GMT FROM: Antonio de Ugarte Postigo at IAA-CSIC A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), A. Sota (IAA-CSIC), and C. Thoene (IAA-CSIC) report: We observed the field of GRB 151118A (Amaral-Rogers et al. GCN 18611) with the 1.5 m OSN telescope in Granada (Spain), starting at 03:17:55 UT (11.42 min after the GRB onset). Observations consisted of 7x300 s exposures in I-band. No new source is detected within the XRT error box. The 3-sigma limiting magnitudes of the individual exposures, and the combined frames are I(Vega) = 21.5 mag, and I(Vega) = 22.5 mag, respectively. The mean time of the combined exposure is 03:37:49 (31.32 min after the burst). Photometry was obtained by comparison with stars from the USNO-B1.0 catalogue.