TITLE: GCN CIRCULAR NUMBER: 11052 SUBJECT: GRB 100805A: Liverpool Telescope afterglow observations DATE: 10/08/05 06:08:10 GMT FROM: Andreja Gomboc at LT,ARI,Liverpool JMU A. Gomboc (U. Ljubljana), C. Guidorzi (U. Ferrara), D. Kopac (U. Ljubljana) report on behalf of a larger collaboration: On 2010 August 05 at 04:14:32 UT the 2-m Liverpool Telescope automatically began observing the Swift GRB 100805A (Hoversten et al., GCN Circ. 11047) with Ringo 2 instrument, continuing with multi-filter (g', r', i') observations at 6.7 min after the GRB trigger. The LT-TRAP procedure automatically identified the optical afterglow at the UVOT position (Hoversten et al., GCN Circ. 11047, Cenko, GCN Circ. 11050) with the following magnitudes: ------------------------------------------------------------------------ T-t0 (s) Exp. (s) Filter Mag ------------------------------------------------------------------------ 400 10 r' 17.92 +- 0.07 421 10 r' 17.93 +- 0.07 726 10 r' 18.36 +- 0.10 3386 60 r' 19.79 +- 0.12 ------------------------------------------------ We confirm the power-law decay index of 0.8 found by P60 (Cenko, GCN Circ. 11051). Magnitudes were calibrated from nearby USNOB1.0 R2 stars. Observations are continuing.