TITLE: GCN CIRCULAR NUMBER: 12368 SUBJECT: GRB 110918A: Gemini-N redshift DATE: 11/09/20 15:30:29 GMT FROM: Nial Tanvir at U.Leicester A.J. Levan (U. Warwick), N.R. Tanvir, K. Wiersema (U. Leicester), E. Berger (Harvard), D. Fox (Penn State) report on behalf of a larger collaboration: We observed the candidate optical afterglow of GRB 110918A reported by Tanvir et al. (GCN12365) with the GMOS-N spectrograph on Gemini-N, Mauna Kea.  Observations began at 20-Sep-2011 12:51 UT.  The trace is well detected and consistent with being a power-law continuum, confirming that this source is very likely the afterglow of the burst detected by the IPN (Hurley et al. GCN12357, see also Cenko et al. GCN12367).  We identify absorption features of MgII (2796A/2804A), MgI (2853A) and CaII (3935A/3970A) at a common redshift of z=0.982 (based on a provisional wavelength calibration). We thank the Gemini staff, particularly Jen Holt, for obtaining these observations.