TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5220 SUBJECT: GRB 060605: ROTSE-III Detection of Optical Counterpart DATE: 06/06/05 18:25:27 GMT FROM: Eli Rykoff at U of Michigan/ROTSE E.S. Rykoff (U Mich), B. E. Schaefer (Louisiana State), report on behalf of the ROTSE collaboration: ROTSE-IIIa, located at Siding Spring Observatory, Australia, responded to GRB 060605 (Swift trigger 213630). The first image was at 18:16:33.3 UT, 48.7 s after the burst (5.4 s after the GCN notice time). The unfiltered images are calibrated relative to USNO A2.0. We detect a 16.3 magnitude, steady source with coordinates: 21:28:37.3 -06:03:30.6 (J2000) start UT mag mlim(of image) ---------------------------------- 18:17:18.0 16.3 16.5 This source is not visible in DSS (second epoch), 2MASS or the MPChecker database. A jpeg image is available at http://www.rotse.net/images/gsb213630_3a001-010_key.jpg Continuing observations are in progress.