TITLE: GCN CIRCULAR NUMBER: 11064 SUBJECT: GRB 100805A: Early RAPTOR Observations DATE: 10/08/05 21:09:45 GMT FROM: James Wren at LANL J. Wren, W.T. Vestrand, P.R. Wozniak, H. Davis, of Los Alamos National Laboratory report: The RAPTOR telescope system responded to Swift trigger 430957 (Hoversten et al., GCN 11047) under fair observing conditions. Our narrow-field instruments began observing the location at 04:13:44.3 UTC, 62.2 seconds after the initial BAT trigger. At 100 seconds after the trigger, we estimate the counterpart to have magnitude R~16.7 +/- 0.3. The object fades steadily reaching R~17.4 +/- 0.3 at 200 seconds after the trigger. It appears to remain near this level for the next 150 seconds or so before resuming the fading behavior. Our unfiltered images were calibrated against the USNO-B1 R-band. Further analysis is ongoing.