TITLE: GCN CIRCULAR NUMBER: 11966 SUBJECT: GRB 110422A: THO optical observations DATE: 11/04/23 04:09:32 GMT FROM: Veli-Pekka Hentunen at Taurus Hill Obs,A95 Veli-Pekka Hentunen, Markku Nissinen and Tuomo Salmi (Taurus Hill Observatory, Varkaus, Finland) report: Taurus Hill Observatory's (A95) Celestron C-14 (OTA) telescope 14" FL 3910 mm with NextGEN 0.5X optical reducer and SBIG ST-8XME camera were used to detect GRB 110422A optical afterglow. The observations were started at 2011-04-22 20:26:30 (UT) and stopped at 2011-04-22 20:57:20 (UT) (~5 hours after the trigger). Six unfiltered observations with 300s exposure time were made. The afterglow was detected at following position RA 7 28 10.98 and DEC +75 06 25.4 consistent those given by Elunko E. et al. (GCN 11958) to within positional errors. The following magnitudes were obtained from the observations using NOMAD1 1651-0051346 (R = 16.040) as the comparison: Tmid(s)+T0 Filter Exp (sec) Mag Mag err Limit (sigma 3) 17285 unfilt 300 19.5 0.7 19.7 17535 unfilt 300 19.6 0.8 19.7 18152 unfilt 300 19.4 0.7 19.7 18462 unfilt 300 19.7 0.9 19.7 A png image of the 3x300sec clear filter observations is available at the following URL link: http://cutenews.kassiopeia.net/data/upimages/GRB_110422A_OA_THO.png