TITLE: GCN CIRCULAR NUMBER: 18386 SUBJECT: GRB 151001A: RATIR Observations DATE: 15/10/02 19:25:37 GMT FROM: V. Zach Golkhou at ASU/RATIR V. Zach Golkhou (ASU), 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 (GSFC/STScI), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC), Jos? A. de Diego (UNAM), Leonid Georgiev (UNAM), Jes?s Gonz?lez (UNAM), Carlos Rom?n-Z??iga (UNAM), Neil Gehrels (GSFC), Harvey Moseley (GSFC), John Capone (UMD), and Vicki Toy (UMD) report: We observed the field of GRB 151001A (Stamatikos, et al., GCN 18373) with the Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the 1.5m Harold Johnson Telescope at the Observatorio Astron?mico Nacional on Sierra San Pedro M?rtir from 2015/10 2.10 to 2015/10 2.15 UTC (11.31 to 12.60 hours after the BAT trigger), obtaining a total of 1.07 hours exposure in the r, i, and z bands. For a source within the Swift-XRT error circle (Beardmore et al., GCN 18376), in comparison with the SDSS DR9 catalog, we obtain the following detections and upper limit (3-sigma): r = 22.69 +/- 0.20 i = 22.59 +/- 0.20 z > 20.03 These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB. The source has faded by about 1 magnitude relative to the earlier observations by the NOT (Kruehler, et al. GCN 18379). We thank the staff of the Observatorio Astron?mico Nacional in San Pedro M?rtir.