TITLE: GCN CIRCULAR NUMBER: 9320 SUBJECT: GRB 090424: optical observations DATE: 09/05/04 00:21:25 GMT FROM: Alexei Pozanenko at IKI, Moscow V. Rumyantsev, K. Antoniuk (CrAO), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration: We observed the afterglow (Cannizzo et al. GCN 9223; Yuan GCN 9224) of the Swift GRB 090424 (Trigger 350311; Cannizzo et al., GCN 9223) in R filter on Apr. 24 (18:25:36 -- 19:23:38) and Apr. 26 (19:57:14 -- 21:01:01) with AZT-11 telescope of CrAO. We detect the afterglow in combined images of both epochs. Astrometry of the afterglow is RA(J2000): 12 38 05.1 Dec(J2000): +16 50 14.72 with uncertainty of 0.5 arcsec. Preliminary photometry of combined images is based on USNO-B1.0 1068-0228255 star RA=12:38:02.33 Dec=+16:51:10.0 is following: T0+ Filter, Exposure, mag., err. (d) (s) 0.1972 R 20x180 19.27 +/-0.06 2.2628 R 20x180 21.0 +/-0.2 The photometry is contaminated with possible host galaxy (Evans et al. GCN 9226). The combined image of the Apr. 24 observation can de found at http://grb.rssi.ru/GRB090424/GRB090424_AZT-11_R.gif