TITLE: GCN CIRCULAR NUMBER: 14818 SUBJECT: GRB 130606A: TAROT Calern observatory early optical observations DATE: 13/06/07 23:34:40 GMT FROM: Alain Klotz at IRAP-CNRS-OMP Klotz A. (IRAP-CNRS-OMP), Gendre B. (IRAP-CNRS-OMP), Boer M., Siellez K., Dereli H., Bardho O. (UNS-CNRS-OCA), Atteia J.L. (IRAP-CNRS-OMP) report: We imaged the field of GRB 130606A detected by SWIFT (trigger 557589) with the TAROT robotic telescope (D=25cm) located at the Calern observatory, France. The observations started 7.1 min after the GRB trigger The elevation of the field increased from 63 degrees above horizon and weather conditions were good. We detect the optical transient (OT) discovered by Jelinek et al. (GCNC 14782). TAROT images are unfiltered. The redshift 5.9 means the OT should emit mainly in the I band. At the present level of analysis we can not give the flux of the OT refered in the I band. We choose the zero point of magnitudes using the star NOMAD-1 1197-0254828 (R=16.43). We refer the TAROT magnitudes to the R magnitude of the reference star (we use CR as the symbol of the clear filtered image calibrated with the R magnitude of the reference star). At 7.85 minutes after the GRB, CR=17.1 The OT is measured continuously until 141 minutes with a mean decay of 0.9. This message may be cited.