TITLE: GCN CIRCULAR NUMBER: 11292 SUBJECT: GRB 100915A: TAROT Calern observatory optical observations DATE: 10/09/19 07:42:30 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 100915A detected by SWIFT (trigger 434178) with the TAROT robotic telescope (D=25cm) located at the Calern observatory, France. The observations started 97s after the GRB trigger (20s after the notice). The elevation of the field decreased from 47 degrees above horizon and weather conditions were good. The first image is trailed with a duration of 60.0s (see the description in Klotz et al., 2006, A&A 451, L39). Time sampling is 10 seconds / pixel. We do not detect any OT with a limiting magnitude of: t0+97s to t0+157s : R > 17.2 We co-added a series of exposures: t0+174s to t0+394s : R > 19.0 Magnitudes were estimated with the nearby USNO-B1 stars and are not corrected for galactic dust extinction. This message may be cited.