GCN Circular 16148
L. Elenin (KIAM), A. Volnova (IKI), I. Molotov (KIAM), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration: After detection of the optical afterglow of GRB 140423A (Elenin et al., GCN 16143; Kaur et al., GCN 16144; Ferrante et al., GCN 16145) and X-ray afterglow (Burrows et al., GCN 16146) we report initial photometry of our first images taken with ISON-NM observatory: UT start t-T0 Exp. Filter OT (mid.,days) (s) 09:01:18 0.02043 30 Clear 17.11 +/- 0.17 09:06:49 0.02426 30 Clear 17.60 +/- 0.21 The photometry is based on star SDSS J130858.37+494547.9 (assuming R = 15.418 +/- 0.018). The finding chart of GRB 140423A afterglow can be found in http://grb.rssi.ru/GRB140423A/GRB140423A_ISON-NM_fc.png Also we report the corect time of observation of the first image in GCN 16143. It should be April, 23, (UT) 09:01:03. We apologize for the misprint.