TITLE: GCN CIRCULAR NUMBER: 13113 SUBJECT: GRB 120326A: Optical observations at Crni Vrh DATE: 12/03/26 13:17:23 GMT FROM: Bojan Dintinjana at OCV B. Dintinjana and B. Mikuz on behalf of PIKA observing program at Crni Vrh Observatory: We observed the afterglow of GRB 120326A (Siegel et al., GCN 13105) with 60 cm Cichocki robotic telescope at Crni Vrh Observatory, Slovenia. The series of twenty 60 second exposures with R filter started at 1:27:50UT, 440 seconds after the burst. We confirm optical afterglow at coordinates by C. Guidorzi (GCN 13111). Photometry results are given in table below. The table contains the time since the Swift GRB detection to the middle of exposure in seconds, R magnitude and photometric error. The magnitudes are derived using comparison stars from the USNO-B1 catalogue. The 3-sigma limiting magnitude in R filter is around magnitude 20.5 ± 0.3 Time [s] R Mag Err. ---------------------------- 440 18.51 0.2 507 19.07 0.2 574 19.21 0.3 641 19.75 0.4 708 19.63 0.6 775 19.10 0.2 842 19.48 0.3 909 19.19 0.2 976 19.77 0.4 1043 19.01 0.2 1110 19.11 0.2 1177 19.18 0.2 1244 19.62 0.3 1311 20.02 0.5 1379 19.35 0.3 1446 19.79 0.4 1513 19.38 0.3 1580 18.97 0.2 1647 19.42 0.3 1714 19.82 0.4 ----------------------------