GCN Circular 3896
Z. Aslan, I. Khamitov (TUG), U. Kiziloglu (METU), E. Gogus (Sabanci Uni.), I. Bikmaev, A. Galeev, N. Sakhibullin (KSU/AST), R. Burenin, M. Pavlinsky, R. Sunyaev (IKI), report: We have continued observing the OT of GRB 050820A (GCN 3829) with the Russian-Turkish 1.5-m telescope (Bakirlitepe, TUBITAK National Observatory, Turkey) using TFOSC in R band. We made 5*300s exposures between UT 22:40 - 23:05, August 27. Using Henden's stars (GCN 3845) present in the frames, we estimated the magnitude of the co-added image as R=22.14+/-0.1 (184.25h after the trigger). The OT is fading with the same power-law decay. Using all the data obtained at the RTT150 (GCN3864, GCN3853) we estimated an alpha index of power-law decay of -1.06+/-0.03. The JPG-image is available at: http://www.tug.tubitak.gov.tr/~irekk/grb/grb050820a/grb050820A_050827r.JPG This message may be cited.