TITLE: GCN CIRCULAR NUMBER: 14024 SUBJECT: GRB 121128A: optical observation in Mondy observatory DATE: 12/11/30 21:19:10 GMT FROM: Alina Volnova at SAI MSU A.Volnova (SAI MSU, IKI), E. Klunko (ISTP), A. Pozanenko (IKI) on behalf of larger GRB follow up collaboration report: We observed the field of the Swift GRB 121128A (Oates et al., GCN 14007) with AZT-33IK telescope of Sayan observatory (Mondy). We took several images in R-filter of 60 s exposure on Nov. 29, between (UT) 10:16:58- 13:33:38 under favorable weather conditions. We do not detect the optical afterglow (Oates et al., GCN 14007; Japelj et al., GCN 14008) in stacked images. A photometry of stacked image t_start, T0+ (mid), filter, exp., UL (3 sigma) (UT) d s 10:16:58 1.28450 R 11200 22.1 is based on the same nearby USNO-B1.0 stars used in our previous observation (Volnova et al., GCN 14019): USNO-B1.0 RA(J2000) Dec(J2000) R 1442-0304687 20:02:23.58 +54:16:58.9 16.67 1442-0304744 20:02:29.58 +54:16:57.0 18.66 1442-0304807 20:02:36.33 +54:17:58.9 18.20 1443-0305750 20:02:37.10 +54:18:34.6 17.72 1443-0305710 20:02:32.72 +54:18:46.9 17.25