TITLE: GCN CIRCULAR NUMBER: 19143 SUBJECT: GRB 160303A: Observations from T150 OSN DATE: 16/03/04 15:46:17 GMT FROM: Antonio de Ugarte Postigo at IAA-CSIC A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), C.C. Thoene (IAA-CSIC), V. Casanova (IAA-CSIC) report on behalf of a larger collaboration: We observed the field of the possibly short GRB 160303A (Beardmore et al., GCN 19126) with the 1.5 m OSN telescope (Sierra Nevada Observatory, Granada, Spain). Observation consisted of 15x300s exposures in R-band, ranging from 01:37-3:00 UT (mean epoch at 15.41 hr after the burst). In the combined image the GRB afterglow (Butler et al., GCN 19131; Emery et al. GCN 19134; de Ugarte Postigo, GCN 19136; Jeong et al. GCN19140; Im et al. GCN 19141; Klose et al. GCN 19142) is seen at a magnitude of r(AB) = 23.67 +/- 0.27 as compared to SDSS stars. This seems to indicate confirm the decay as compared with the data of RATIR (Butler et al., GCN 19131), NOT (de Ugarte Postigo, GCN 19136) and CQUEAN (Jeong et al. GCN19140), BOAO (Im et al. GCN 19141) and FORS (Klose et al. GCN 19142). In any case the possible decay would be shallower than the typical GRB, with a decay slope of alpha ~ 0.5 (F_nu ~ t^-alpha).