GCN Circular 16221
L. Elenin (KIAM), A. Volnova (IKI), I. Molotov (KIAM), A. Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration: We observed of the field of Swift GRB GRB 140502A with 0.4-m telescope of ISON-NM observatory starting on May, 02 (UT) 08:31:32, i.e. 72 s after BAT trigger (Swenson et al., GCN 16202). We took series of unfiltered images of 30 s - 60 s exposures. A bright star (USNO-B1.0 1389-0392112) already mentioned (Oates et al., GCN 16210) lies within enhanced XRT error circle (Goad et al., GCN 16206). We investigate variability of a possible OT in presence in near vicinity of the bright star. The upper limit of possible variation of the OT is 16.6m within any of 60 s interval of our observations between (UT) 08:31:32 and 09:24:25 which can be considered as an upper limit on the OT associated with GRB 140502A. Formal photometry and limiting magnitude of point-like source in the observed field is following UT start t-T0 Exp. Filter OT UL(3 sigma) (mid.,days) (s) 08:31:32 0.00383 10*30 None n/d 18.8 and based on nearby USNO-B1.0 stars, R2 magnitudes.