TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2184 SUBJECT: GRB030429, possible optical counterpart DATE: 03/05/01 07:52:29 GMT FROM: Arne A. Henden at USNO/USRA A. Gilmore and P. Kilmartin (U. Canterbury) and A. Henden (USRA/USNO) report: We have imaged part of the error circle for the HETE burst GRB030429 (HETE trigger 2695) with the Mt. John 0.6m telescope (unfiltered, using Rc zeropoint) and the USNOFS 1.55m telescope (Rc filter). We find one fading object that may be the optical counterpart to GRB030429. This object does not appear on the DSS-2 red plate. Its position, along with one comparison star from USNO-A2.0, is OT 12:13:07.50 -20:54:49.7 J2000 (err: +/- 0.3arcsec) Star A 12:13:01.05 -20:56:06.6 Rc=12.6 where coordinates are based on USNO-A2.0. A 4x4arcmin R-band finding chart can be found at ftp://ftp.nofs.navy.mil/pub/outgoing/aah/grb/grb030429r.jpg The candidate is about 7arcsec southwest of a 19th magnitude star. Photometry of the candidate with respect to Star A, starting about 3.5hrs after the burst, yields: UTmid CRmag CRerr Apr 29.591 19.34 0.11 Apr 29.600 19.43 0.13 Apr 29.616 19.71 0.16 Apr 29.660 19.87 0.19 It has faded more than another magnitude by May 01.25. The color of the candidate is blue, but accurate colors will be posted after calibration reductions are complete. These observations were made as part of the AAVSO GRB Network, and supported by a grant from the Curry Foundation.