TITLE: GCN CIRCULAR NUMBER: 17762 SUBJECT: GRB 150424A: RATIR Observations DATE: 15/04/25 17:26:07 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 the short-duration GRB 150424A (Beardmore, et al., GCN 17743) 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 2015/04 25.14 to 2015/04 25.28 UTC (19.54 to 23.05 hours after the BAT trigger), obtaining a total of 2.4 hours exposure in the r, i, and z bands. The optical afterglow (Perley, GCN 17745; Marshall & Beardmore, GCN 17751; Malesani, et al., GCN 17756; Kann, et al., GCN 17757) is well-detected. In comparison with 2MASS and the USNO-B1 catalog, we obtain the following detections and upper limit (3-sigma): r 21.92 +/- 0.11 i 21.65 +/- 0.09 z > 20.17 These magnitudes are in the AB system and are not corrected for Galactic extinction in the direction of the GRB. Compared to the earlier NOT and GROND observations, the source appears to be continuing its strong fade (Kann, et al. GCN 17757). We thank the staff of the Observatorio Astronómico Nacional in San Pedro Mártir.