TITLE: GCN CIRCULAR NUMBER: 12448 SUBJECT: GRB111016A: D50 optical limit DATE: 11/10/18 15:08:32 GMT FROM: Martin Jelinek at Inst.Astrophys.Andalucia,Granada M. Blazek (AsU AV), R. Hudec (AsU AV), M. Jelinek (IAA-CSIC), C. Polasek (AsU AV) and J. Strobl (AsU AV) "We observed the field of GRB 111016A (Mangano et al., GCN 12439) with 0.5m robotic telescope D50 in Ondrejov observatory (Czech Republic). The observation started at 01:59:08 UT on October 17, 2011, approx. 5.5 hours after the Swift trigger. We report no detection of the optical counterpart on the unfiltered images within the error circle given by SWIFT-XRT (Evans et al., GCN 12441). The upper limit of 19.5 mag in R-band was estimated using nearby sources from GSC2.2 catalogue."