TITLE: GCN CIRCULAR NUMBER: 18503 SUBJECT: GRB 151027A: THO optical observations DATE: 15/10/28 02:54:58 GMT FROM: Veli-Pekka Hentunen at Taurus Hill Obs,A95 Veli-Pekka Hentunen, Markku Nissinen and Tuomo Salmi (Taurus Hill Observatory, Varkaus, Finland) report: We have detected GRB 151027A optical afterglow at Taurus Hill Observatory (A95) using Meade 16" ACF 0.40-m/8.0 telescope and SBIG ST-8XME CCD. The observations were started at 2015-10-27 17:11:39 (UT). Eight photometric R filter and eight photometric V filter images with 300 sec exposure time were taken. The afterglow was detected at the following position RA 18:09:56.72 and DEC +61:21:13.2. The following magnitudes were obtained from the observations using NOMAD1 1512-0243178 (R=13.200 and V=13.670) as a comparison star: Tmid(h)+T0 Filter Exp. time Mag Mag. Err. 13.393 R 4x300s 17.06 0.12 13.747 V 4x300s 17.56 0.25 14.103 R 4x300s 17.06 0.09 14.457 V 4x300s 17.49 0.10 --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus