TITLE: GCN CIRCULAR NUMBER: 9440 SUBJECT: GRB 090530: PAIRITEL NIR Detections DATE: 09/05/30 04:30:03 GMT FROM: Adam Morgan at U.C. Berkeley A. N. Morgan, D. A. Perley, J. S. Bloom, (UC Berkeley), and D. Starr (UCB, LCOGT) report: We observed the field of GRB 090530 (Cannizzo et al., GCN 9438) with the 1.3-m PAIRITEL located at Mt Hopkins, Arizona. Observations began at 2009-05-30 03:19:30 UT, 72 seconds after the Swift Trigger. We detect the optical afterglow (Cannizzo et al., GCN 9438, Flewelling et al., GCN 9439) in mosaics taken simultaneously in the J, H, and Ks filters. The preliminary photometry yields: post_burst t_mid (min) exp(s) filt mag merr 8.33 424 J 16.4 0.1 8.33 424 H 15.4 0.1 8.33 424 Ks 15.0 0.1 All magnitudes given in the Vega system, calibrated to 2MASS. No correction for Galactic extinction has been made to the above reported values. Observations are ongoing. [GCN OPS NOTE(30may09); The typo in the Subject line was changed from "090515" to "090530".]