TITLE: GCN GRB OBSERVATION REPORT NUMBER: 1949 SUBJECT: GRB030323, possible optical counterpart DATE: 03/03/24 19:40:26 GMT FROM: Arne A. Henden at USNO/USRA A. Gilmore and P. Kilmartin (U. Canterbury) and A. Henden (USRA/USNO) report: We have imaged the inner 20x20arcmin of the error circle for the HETE burst GRB030323 (HETE trigger 2640) with the Mt. John 0.6m telescope (unfiltered, using Rc zeropoint) and the USNO 1.0m telescope (Rc filter). Located in the northern part of the error circle, we find one fading object that may be the optical counterpart to GRB030323. This object does not appear on any of the ESO/AAO red plates. Its position, along with two preliminary comparison stars (photometry from Henden, GCN 1948), is: Star R.A. (2000) Dec. Rc A 11 06 15.21 -21 47 19.4 14.91 B 11 06 08.36 -21 45 42.5 16.94 OT 11 06 09.38 -21 46 13.3 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/grb030323r.jpg Photometry of the candidate with respect to these two stars yields: UTmid(hr) mag Filter 07.5868 18.69 Rc 10.4750 19.56 CR 12.2083 19.72 CR 13.6555 19.96 CR 14.7333 20.42 CR Photometric errors range from 0.06mag at the beginning to 0.4mag towards the end. These observations were made as part of the AAVSO GRB Network, and supported by a grant from the Curry Foundation. [GCN OPS NOTE (25mar03): The acknowledgement sentence at the end was added as per author's request.]