TITLE: GCN CIRCULAR NUMBER: 15224 SUBJECT: GRB 130912A: WHT confirmation of optical counterpart DATE: 13/09/13 12:59:55 GMT FROM: Andrew Levan at U.of Leicester N.R. Tanvir, K. Wiersema (U. Leicester), A.J. Levan (U. Warwick) report for a larger collaboration: "We observed the location of GRB 130912A (D'Elia et al. GCN 15212) with the William Herschel Telescope, beginning at approximately 05 UT on 13 September 2013, roughly 20 hours after the burst trigger. At this epoch we obtained observations in the g,i and J-bands utilising ACAM and LIRIS. At the location of the counterpart identified by Tanga et al. (GCN 15214) and Cenko et al. (GCN 15222) we detect no source in our g-band observations (limiting magnitude g~25), and a source which is only weakly detected in the i-band and J-band (i~24). This implies that the light observed at earlier epochs when the source was measured at r=22 was due to a significant contribution from the optical transient, and that any underlying host galaxy is faint."