TITLE: GCN CIRCULAR NUMBER: 11889 SUBJECT: GRB 110402A: fading optical afterglow DATE: 11/04/06 17:50:56 GMT FROM: Alexei Pozanenko at IKI, Moscow V. Rumyantsev (CrAO), A. Pozanenko (IKI), A. Volnova (SAI MSU) on behalf of larger GRB follow up collaboration report: We observed the field of GRB 110402A (Ukwatta et al. GCN 11857) with Shajn telescope of CrAO observatory on Apr. 3 between (UT) 18:41 and 19:59 under seeing of about 2.6 arsces. We took several frames with exposure of 60s in R-band. On a stacked image we detected the optical counterpart (Mundell et al. GCN 11858, Leloudas et al. GCN 11859). The counterpart has coordinates (J2000) RA = 13h 09m 36.63s, Dec = +61d 15' 09.5'' with uncertainty of 0.1" in both coordinates which are fully compatible with initial counterpart coordinates (Mundell et al. GCN 11858). The photometry is based on the USNO B1.0 star 1512-0199231 (13 09 43.16 +61 14 38.5) assuming R=16.71. T0+ Filter, Exposure, mag. uplim (3 sigma) (mid, d) (s) 1.79672 R 73x60 23.11+/-0.12 24.4