TITLE: GCN CIRCULAR NUMBER: 26882 SUBJECT: GRB 200125A: RATIR Optical Observations DATE: 20/01/26 01:39:15 GMT FROM: Alan M Watson at UNAM Alan M. Watson (UNAM), Nat Butler (ASU), Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox (STScI), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (UVI), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC), Jes��s Gonz��lez (UNAM), Carlos Rom��n-Z����iga (UNAM), Harvey Moseley (GSFC), John Capone (UMD), V. Zach Golkhou (U. Wash.), and Vicki Toy (UMD) report: We observed the field of GRB 200125A (Lien et al., GCN Circ. 26876) 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 2020/01 25.48 to 2020/01 25.56 UTC (0.03 to 1.89 hours after the BAT trigger), obtaining a total of 1.40 hours exposure in the r and i bands. We detect a a source within the enhanced Swift-XRT error circle (Beardmore et al., GCN Circ. 26878). In comparison with the USNO-B1 and 2MASS catalogs, we obtain the following detections: r = 21.02 +/- 0.05 i = 19.54 +/- 0.02 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 Astron��mico Nacional in San Pedro M��rtir.