TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3953 SUBJECT: GRB050908: VLT R-band decay index. DATE: 05/09/08 18:09:26 GMT FROM: Angelo Antonelli at Obs. Astro. di Roma S. Piranomonte, L. Calzoletti (INAF/OAR), P. D'Avanzo (INAF/OABr), L.A. Antonelli (INAF/OAR), F. Patat, C. Ledoux (ESO), D. Malesani (SISSA/ISAS), G. Chincarini (INAF/OABr & Univ. Milano-Bicocca), S. Covino, D. Fugazza, G. Tagliaferri(INAF/OABr), F. Fiore and L. Stella (INAF/OAR), report on behalf of the MISTICI collaboration: "We observed the optical afterglow (Torii, GCN 3943; Cenko, Fox & Berger, GCN 3944) of GRB 050908 (Goad et al., GCNs 3942, 3946) with the ESO-VLT UT2, equipped with the FORS1 instrument. R-band observations were performed in Rapid Response Mode (RRM) on Sep 8.268 UT and as a ToO on Sept 8.415 UT (42 and 255 minutes after the GRB respectively). During the two epoch observations the afterglow decays as a power law having decay index of -0.93+/-0.05. This message may be cited" [GCN OPS NOTE(10sep05): Per author's request, "N. Patat" was changed to "F. Patat".]