TITLE: GCN CIRCULAR NUMBER: 14107 SUBJECT: GRB 121226A: Zadko observatory - Gingin optical observations DATE: 12/12/26 23:18:31 GMT FROM: Alain Klotz at CESR-CNRS A. Klotz (IRAP-CNRS-OMP), D. Macpherson (UWA/ICRAR), D. Coward (UWA), B. Gendre (ASDC/INAF-OAR), M. Boer (UNS-CNRS-OCA), A. Williams (PO-UWA), R. Martin (PO-UWA) report: We imaged the field of GRB 121226A detected by SWIFT (trigger 544027) with the Zadko robotic telescope (D=100cm) located at the observatory - Gingin, Australia. The observations started 62.8s after the GRB trigger (38.6s after the notice). The elevation of the field increased from 64 degrees above horizon and weather conditions were good. The first image is trailed with a duration of 60.0s (see the description in Klotz et al., 2006, A&A 451, L39). We do not detect any OT in the XRT error box with a limiting magnitude of: t0+62.8s to t0+122.8s : Rlim 17.5 The second image is 30.0s exposure in tracking mode: t0+138s to t0+168s : Rlim 18.7 We co-added a series of exposures: t0+138s to t0+335s : Rlim 19.4 Magnitudes were estimated with the nearby USNO-B1 stars and are not corrected for galactic dust extinction. This message may be cited.