TITLE: GCN CIRCULAR NUMBER: 15222 SUBJECT: GRB 130912A: P60 Observations DATE: 13/09/12 21:02:47 GMT FROM: S. Bradley Cenko at Caltech S. B. Cenko (NASA/GSFC), V. Sudilovsky, M. Tanga, and J. Greiner (MPE Garching), report on behalf of a larger collaboration: We have imaged the field of the Swift short GRB130912A (D'Elia et al., GCN 15212) with the robotic Palomar 60 inch telescope in the r', i', and z' filters. Observations began at 8:48 UT on 2013 September 12 (13 min after the Swift trigger). Within the enhanced XRT error circle (Beardmore et al., GCN 15217) we detect the faint source reported by Tanga et al. (GCN 15214) in all three filters. Using calibration stars from GROND, we measure an AB magnitude of r' = 21.77 +/- 0.20 mag at a mean time of 8:58 UT and r' = 22.09 +/- 0.25 at 09:28 UT (23 and 53 min after the Swift trigger, respectively). The lack of significant variability implies either a shallow afterglow decay index, or this source may be the host galaxy of GRB130912A, as suggested by Tanga et al. (GCN 15214).