GCN Circular 11054
J. Gorosabel, V. Terron, M. Jelinek, A.J. Castro-Tirado (IAA-CSIC), report on behalf of a larger collaboration: "Following the detection of GRB 100805A by Swift (Hoversten et al. GCNC 11047) we carried out I-band observations with the 1.23m telescope at Observatory of Calar Alto. The first exposure started on Aug 5.1824 UT (~10 minutes post burst) with an integration time of 120s. The optical afterglow is well detected with a preliminary magnitude of I ~ 16.9, against USNO-B1.0 field stars."