GCN Circular 3911
Klotz, A. (CESR-OMP), Boer M. (OHP), Atteia J.L. (LATT-OMP) report: We imaged the field of GRB 050904 detected by SWIFT (trigger 153514) with the TAROT robotic telescope (D=25cm) located at the Calern observatory, France. First image was acquired 86s after the GCN trigger. The field had an elevation of 60 degrees above horizon and weather conditions were good. We detected no new source comparing our unfiltered images with the USNO-B catalog. From the first frame we give an early limit: Day : 2005-09-04 UT-start UT-end (sec since GRB) Exp(s) R-mag 01:53:10.33 - 01:54:08.33 86 - 101 15 >16.0 We co-added 13 first frames and no new source is detected: Day : 2005-09-04 UT-start UT-end (sec since GRB) Exp(s) R-mag 01:53:10.33 - 02:00:18.74 86 - 515 360 >18.5 Limiting magnitude was estimated with the nearby USNO-B1 stars. This message can be cited.