TITLE: GCN CIRCULAR NUMBER: 7833 SUBJECT: GRB080605: optical observations DATE: 08/06/06 04:22:14 GMT FROM: Alexei Pozanenko at IKI, Moscow V. Rumyantsev (CrAO), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration: We observed the optical afterglow (Kann, et al., GCN 7829; Holland et al., GCN 7830; Gomboc et al., GCN 7831) of Swift GRB 080605 (Sbarufatti et al., GCN 7828) in R and I bands on June 05 Zeiss-1000 (Simeiz) telescope of CrAO observatory under not optimal weather conditions. Based on USNO-B1.0 star RA (J2000) = 17 28 29.92, Dec. (J2000) = +04 00 36.5, R2=15.90 we estimated brightness of the optical afterglow in first frames: UT, Exposure, R_mag, (start time) 2008-06-05T23:55:58 120 s 17.9 2008-06-06T00:00:34 120 s 18.4 During observations the afterglow is clearly faded. Coordinates of the afterglow with uncertainties of 0.3": RA(2000): 17 28 30.01 Dec(2000): +04 00 56.4 A finding chart can be found at http://grb.rssi.ru/GRB080605/grb080605_080605_z1000.gif The message may be cited.