TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3139 SUBJECT: GRB050319: RTT150 Optical Observations DATE: 05/03/23 08:22:43 GMT FROM: Umit Kiziloglu at Middle East Tech.U,Phys.Dept U. Kiziloglu, S. Balman, A. Baykal (METU), Z. Aslan, I. Khamitov, K. Uluc (TUG), S. Evren (EgeU), A. Alpar (Sabanci U.), R. Burenin, M. Pavlinsky (IKI), R. Sunyaev (IKI, MPA), I, Bikmaev (KSU) report : We observed the field centered on the Swift GRB 041006 (Rykoff et al. GCN 3116, Krimm et al., GCN 3117, GCN 3119) with the TUG (TUBITAK National Observatory, Turkey) 1.5-m Russian-Turkish Telescope (RTT150). We obtained 8x300s 6x120s 3x60s R band images on 2005.03.19 starting at 17:26:36 UT using the imaging ANDOR CCD. The seeing was 1.8"-2.1". We further obtained 6x300 s R band images on 2005.03.20 and 2005.03.21 with RTT150. The seeing was poor with Moon. We calculated the R magnitudes below using the USNO B1.0 Catalog. Observation (UT) R_mag -------------------- ---------------------- 2005 March 19, 18:12 20.14 +/- 0.09 2005 March 21, 00:16 21.3 +/- 0.6 1 Sigma frame upper limit 2005 March 21, 17:58 21.1 +/- 0.3 This message can be cited.