TITLE: GCN CIRCULAR NUMBER: 11217 SUBJECT: GRB100904A: BOOTES-3 Upper Limit DATE: 10/09/05 20:06:20 GMT FROM: Juan Carlos Tello at IAA-CSIC J.C. Tello, J. Gorosabel, A.J. Castro-Tirado (IAA-CSIC, Granada) P. Kubanek (IAA-CSIC and IPL-UV) W. Allen (Vintage Lane Obs.), Ph. Yock and Kuan-Yu Lin (Auckland Univ.), report on behalf of a larger collaboration: "We have carried out observations of the Swift GRB 100904A (Ukwatta et al. GCNC 11203) on Sep 4.2982 - 4.3145 UT (~5.98 hr after the onset of the burst, mean observing time) with the 0.6m Yock-Allen robotic telescope (BOOTES-3) located in Blenheim, New Zealand. Observations were carried out at high airmass (~ 7). We do not detect any optical source within the Swift-BAT refined analysis error circle (Ukwatta et al. GCNC 11207). The 3 sigma limiting magnitude of the co-added unfiltered image (Texp=16x60s) is R ~ 18.0, using USNO-B1.0 as photometric reference." [GCN OPS NOTE(06sep10): Per author's request, K-YL was added to the author list.]