TITLE: GCN CIRCULAR NUMBER: 14876 SUBJECT: GRB 130612A: PAIRITEL NIR Afterglow Observations DATE: 13/06/12 04:07:12 GMT FROM: Adam Morgan at U.C. Berkeley A. N. Morgan (UC Berkeley) reports: We observed the field of GRB 130612A (Racusin et al., GCN 14874) with the 1.3m PAIRITEL located at Mt. Hopkins, Arizona. Observations began at 2013-Jun-12 03h29m25s UT, 6.65 minutes after the Swift Trigger. In mosaics (consisting of 48 ~8 second images for a total effective exposure time of 6.3 minutes) taken simultaneously in the J, H, and Ks filters, we detect the optical afterglow (Racusin et al., GCN 14874; Melandri et al., GCN 14875). The preliminary K-band reduction is corrupted. The observations quoted below began at 3:32 UT, ~9.5 minutes after the Swift trigger, after an automatic pointing reset by our telescope. The preliminary photometry yields: post burst t_mid (m) exp.(m) filt mag m_err 14.6 6.3 J 17.26 0.12 14.6 6.3 H 16.78 0.15 Observations are ongoing. All magnitudes are given in the Vega system, calibrated to 2MASS. No correction for Galactic extinction has been made to the above reported values.