GCN Circular 13893
A. N. Morgan, and J. S. Bloom (UC Berkeley) report: We observed the field of GRB 121024A (Pagani et al., GCN 13886) with the 1.3m PAIRITEL located at Mt. Hopkins, Arizona. Observations began at 2012-Oct-24 07h31m47s UT, ~4.6 hours after the Swift Trigger. In mosaics (effective exposure time of 0.46 hours) taken simultaneously in the J, H, and K filters, we detect a source at the optical afterglow location (Pagani et al., GCN 13886; Klotz et al., GCN 13887; Jelinek et al., GCN 13888; LaCluyze et al., GCN 13889; Knust et al. GCN 13891). The preliminary photometry yields: post burst t_mid (hr) exp.(hr) filt mag m_err 6.06 0.46 J >18.4 3sig 6.06 0.46 H 17.1 0.2 6.06 0.46 Ks >16.2 3sig All magnitudes are given in the Vega system, calibrated to 2MASS. No correction for Galactic extinction has been made to the above reported values.