TITLE: GCN CIRCULAR NUMBER: 16164 SUBJECT: GRB 140423A, Optical Observations DATE: 14/04/24 10:12:16 GMT FROM: Shashi Bhushan Pandey at ROTSE S. B. Pandey, Brajesh Kumar and Aditi Agarwal (ARIES Nainital India, on behalf of larger Indian GRB collaboration) We observed the Swift GRB 140423A field (Sonbas et al., GCN 16142) using 1.3m DFOT telescope at Devasthal operated by ARIES Nainital, India. Observations were started at 14:36:07 UT on 2014-04-23 (~6 h after the burst). The optical counterpart of the burst (Elenin et al., GCN 16143; Kaur et al., GCN 16144; Ferrante et al., GCN 16145; Chester et al., GCN 16147) was clearly detected in individual frames of exposure time 300s each. The preliminary photometry is as following: (UT)Start filter exp(sec) mag 14:36:07 R_c 300 20.12 +/- 0.08 14:42:50 I_c 300 19.76 +/- 0.15 The photometry was performed in comparison to nearby USNO stars. This message may be cited.