TITLE: GCN CIRCULAR NUMBER: 18001 SUBJECT: GRB 150710A: RATIR Observations DATE: 15/07/10 04:58:33 GMT FROM: Nat Butler at Az State U Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM), Chris Klein (UCB), Ori Fox (UCB), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (ORAU/GSFC), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC), José A. de Diego (UNAM), Leonid Georgiev (UNAM), Jesús González (UNAM), Carlos Román-Zúñiga (UNAM), Neil Gehrels (GSFC), and Harvey Moseley (GSFC) report: We observed the field of possible GRB 150710A (trigger 648437; Bernardini, et al., GCN 18000) with the Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the 1.5m Harold Johnson Telescope at the Observatorio Astronómico Nacional on Sierra San Pedro Mártir from 2015/07 10.16 to 2015/07 10.20 UTC (3.47 to 4.31 hours after the BAT trigger), obtaining a total of 0.71 hours exposure in the r, i, and z bands. For a source within the Swift-XRT error circle, in comparison with the SDSS DR9 catalog, we obtain the following upper limits (3-sigma): r > 23.4 i > 23.2 z > 19.4 These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the possible GRB. We thank the staff of the Observatorio Astronómico Nacional in San Pedro Mártir. Further observations are ongoing.