TITLE: GCN CIRCULAR NUMBER: 8343 SUBJECT: GRB 081008: ROTSE-III Detection of Optical Counterpart DATE: 08/10/08 20:04:04 GMT FROM: Eli Rykoff at UCSB E.S. Rykoff (UCSB), report on behalf of the ROTSE collaboration: ROTSE-IIIc, located at the H.E.S.S. site at Mt. Gamsberg, Namibia, responded to GRB 081008 (Swift trigger 331093). The first image was at 19:58:51.3 UT, 41.9 s after the burst (8.3 s after the GCN notice time). The unfiltered images are calibrated relative to USNO A2.0. We detect a 14.5 magnitude, brightening source with coordinates: 18:39:50.0 -57:25:52.0 (J2000), with positional uncertainty of 1" or better start UT mag mlim(of image) ---------------------------------- 19:58:51.3 14.5 16.2 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/gsb331093_3c00_img.jpg Continuing observations are in progress.