TITLE: GCN CIRCULAR NUMBER: 7625 SUBJECT: GRB 080413A: Liverpool Telescope and Faulkes Telescope South optical observations DATE: 08/04/16 17:23:09 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 Liverpool Telescope observed the field of GRB 080413A (trigger=309096, Beardmore et al. GCN 7594) under poor weather conditions starting 2-hr after the trigger. Observations continued with the Faulkes Telescope South. In our coadded frames we do not detect any source at the position of the optical afterglow (Beardmore et al. GCN 7594, Rykoff & Rujopakarn GCN 7593) down to the limiting magnitudes reported below. Telescope Filter Tstart(hr) Tstop(hr) Exposure(s) M_lim ---------------------------------------------------------------------- Liverpool R 2.0 2.5 760 15.7 Faulkes South R 12.2 12.2 30 19.2 I 12.2 13.1 2080 21.7 ---------------------------------------------------------------------- Magnitudes were calibrated with respect to USNOB1 R2 and I.