TITLE: GCN CIRCULAR NUMBER: 7626 SUBJECT: GRB 080413B: Faulkes Telescope South optical afterglow observations DATE: 08/04/16 17:48:34 GMT FROM: Andreja Gomboc at LT,ARI,Liverpool JMU A. Gomboc (Ljubljana), C. Guidorzi (U. Bicocca/INAF-OAB), A. Melandri, I.A. Steele, C.G. Mundell, D.F. Bersier, M.F. Bode, M.J. Burgdorf, S.N. Fraser, S. Kobayashi, C.J. Mottram, R.J. Smith (Liverpool JMU), P. O'Brien, N. Bannister, N. Tanvir (U. Leicester) report on behalf of larger GRB collaboration: The 2-m Faulkes Telescope South observed the field of GRB 080413B (trigger=309111, Stamatikos et al. GCN 7598) starting 8.7-hr after the trigger time. We detect the optical afterglow (Stamatikos et al. GCN 7598, Kruehler et al. GCN 7599, Antonelli et al. GCN 7600) and measure the following magnitudes: Filter T_mid(hr) Exposure(s) Mag ---------------------------------------------------------------------- R 8.74 30 19.00 +/- 0.15 I 8.90 640 18.91 +/- 0.05 I 9.20 1080 19.15 +/- 0.05 I 9.54 1080 19.22 +/- 0.06 ---------------------------------------------------------------------- Magnitudes were calibrated with respect to USNOB1 R2 and I.