GCN Circular 7146
S. Sergeev, V. Rumyantsev (CrAO), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration: We observed the optical afterglow (Schaefer et al. GCN 6948) of GRB071020 (Tueller et al. GCN 6954) in I and B bands on Oct.10-11 between (UT) 23:51:34 - 01:11:47 with AZT-8 telescope of CrAO. We detected the afterglow in I-band, and not detected it in B-band. Based on SDSS stars (Cool et al. GCN 6950) RA=119.66618, Dec=32.84706; RA=119.68899, Dec=32.84803; RA=119.66782, Dec=32.85465 we estimated brightness of the optical afterglow on a stacked images: T0+, Exposure, Filter, mag., UL (mid time) 0.730 d 12x90 s I 20.5 +/-0.3 20.5 0.728 d 12x180 s B n/d 21.0 The message may be cited.