TITLE: GCN CIRCULAR NUMBER: 11106 SUBJECT: GRB 100816A: TAROT Calern observatory optical detection DATE: 10/08/16 14:38:10 GMT FROM: Alain Klotz at CESR-CNRS Klotz A. (CESR-OMP), Gendre B. (IASF), Boer M. (OHP-OAMP), Atteia J.L. (LATT-OMP) report: We imaged the field of GRB 100816A detected by SWIFT (trigger 431764) with the TAROT robotic telescope (D=25cm) located at the Calern observatory, France. The observations started 1339s after the GRB trigger The elevation of the field increased from 72 degrees above horizon and weather conditions were good. We co-added a series of 30s unfiltered exposures. We detect the OT mentioned by Oates et al. 2010 (GCNC 11102) very close to the limiting magnitude of the image : start exp. = 1339s end exp. = 1601s R ~ 19.2 Magnitudes were estimated with the nearby star NOMAD-1 1165-0624306 and are not corrected for galactic dust extinction.