TITLE: GCN CIRCULAR NUMBER: 17894 SUBJECT: GRB 150530A: RATIR Optical Observations DATE: 15/05/31 19:31:54 GMT FROM: Alan M. Watson at Instituto de Astronomia UNAM Alan M. Watson (UNAM), Nat Butler (ASU), 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 GRB 150530A (Starling et al., GCN 17888) 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 2015/05 31.32 to 2015/05 31.45 UTC (20.08 to 23.21 hours after the BAT trigger), obtaining a total of 2.49 hours exposure in the r, i, and z bands. For a source within the Swift-XRT error circle, in comparison with 2MASS, we obtain the following upper limits (3-sigma): r > 24.42 i > 24.18 z > 20.44 These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB. We thank the staff of the Observatorio Astronómico Nacional in San Pedro Mártir.