TITLE: GCN CIRCULAR NUMBER: 10962 SUBJECT: GRB 100713A: optical observation in Maidanak DATE: 10/07/16 19:33:40 GMT FROM: Alexei Pozanenko at IKI, Moscow A. Pozanenko (IKI), A. Volnova (SAI MSU), B. Satovski (Astrotel), M. Ibrahimov (MAO) report on behalf of larger GRB follow-up collaboration: We observed the field of the INTEGRAL GRB 100713A (Mereghetti et al. GCN 10951) with AZT-22 telescope of Maidanak observatory in R band between July 13 (UT) 18:21 -- 18:56 under photometric conditions and seeing ~0.7". A possible faint source (S/N = 2.2) was detected at coordinates (J2000) RA=17 00 48.12 Dec = +28 23 40.2 with uncertainties 0.15" in both coordinates. The source is at the edge of enhanced XRT error circle (D'Elia et al. GCN 10960). At this time we cannot confirm the nature of the source and comparison with TNG observation (D'Avanzo et al. GCN 10954) and/or additional observation is necessary. The SDSS object reported by D'Avanzo et al. (GCN 10954) and Nardini et al. (GCN 10956) is also clearly detected. The photometry is based on several SDSS field stars and Lupton ugriz -> R transformations : T0+ Filter, Exposure, mag. Upper limit (3 sigma) (mid, d) (s) 0.16830 R 300*6 24.4+/-0.5 24.0 The finding chart can be found at http://grb.rssi.ru/GRB100713A/GRB100713A_AZT22.png We thank Alexander Gusev for performing the observations and for his support.