GCN Circular 34611
R. Strausbaugh (Eastern Illinois University), A. Cucchiara (NASA) report on behalf of a larger collaboration: We observed the Swift GRB 230903A (D'ai et al., GCN 34610) field with the LCOGT 1-meter Sinistro instrument at the South African Astronomical Observatory site, on September 3, from 20:08 to 20:41 UT (corresponding to 2.77 to 3.32 hours from the GRB trigger time) with the Bessel R and I filters. We performed a series of 3x300s exposures in each band. We do not detect a source within the Swift-XRT error region (D'Ai et al., GCN 34610) in either band. The following upper limits are calculated using the USNO-B1.0 catalog as reference: R > 20.5 I > 19.0 These magnitudes are not corrected for galactic extinction.