TITLE: GCN GRB OBSERVATION REPORT NUMBER: 1343 SUBJECT: GRB020124 optical observations with RIBOTS/RIMOTS DATE: 02/04/09 03:12:04 GMT FROM: Yuji Urata at RIKEN N. Kawai, Y. Urata (Titech/RIKEN), M. Kohama, K. Torii (RIKEN), A. Yoshida (AGU/RIKEN), K. Ayani, T. Kawabata (Bisei Astronomical Observatory), M. Chaya, H. Shibata, K. Sakamoto, M. Yamauchi (Miyazaki Univ.) on behalf of the RIBOTS/RIMOTS team We have observed covering the entire error circle of GRB020124 (Ricker et al. GCN 1220) field with the RIBOTS/RIMOTS 30-cm telescopes. The observations started at an early epoch (+1.3 hours after the burst). All the images were taken with 15 sec exposure and stacked for deeper inspection. From a comparison with the DSS-2 images we did not identify any new point source for the GRB. We summarize the observing time and the R-band limiting magnitude (SN=3), which was estimated by the comparison of our non-filter data with the R band field photometry by Henden (GCN 1251). Summary of observations on 2002/01/24 Time(UT) Limiting R mag start end (SN=3) 12:00 12:57 17.8 15s x 61 frames combined (RIMOTS) 16:19 16:59 18.6 15s x 59 frames combined (RIBOTS) 17:00 17:59 18.8 15s x 87 frames combined (RIBOTS) 18:00 18:59 19.1 15s x 87 frames combined (RIBOTS) 19:00 19:59 19.1 15s x 87 frames combined (RIBOTS) 20:00 20:59 17.7 15s x 87 frames combined (RIBOTS) This message may be cited.