TITLE: GCN CIRCULAR NUMBER: 13624 SUBJECT: GRB 120811C: TAROT Calern observatory optical observations DATE: 12/08/11 21:03:08 GMT FROM: Alain Klotz at CESR-CNRS Klotz A. (IRAP-CNRS-OMP), Gendre B. (ASDC/INAF-OAR), Boer M. (UNS-CNRS-OCA), Atteia J.L. (IRAP-CNRS-OMP) report: We imaged the field of GRB 120811C detected by SWIFT (trigger 530689) with the TAROT robotic telescope (D=25cm) located at the Calern observatory, France. The observations started 3.98h after the GRB trigger. The elevation of the field decreased from 50 degrees above horizon and weather conditions were good. We co-added a series of exposures but we do not find any optical transcient at the afterglow position (Barlow et al. GCNC 13622, Denisenko et al. GCNC 13623): ------------------------------- T-T0 start | T-T0 End | Mag. | -----------+----------+-------+ 246 min | 313 min | >19.5 | ------------------------------- Magnitudes were estimated with the nearby USNO-B1 stars and are not corrected for galactic dust extinction. This message may be cited.