TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2899 SUBJECT: GRB041223: ROTSE-III Optical Observations DATE: 04/12/23 20:08:44 GMT FROM: Eli Rykoff at Univ. of Michigan/ROTSE E. Rykoff (U. Michigan) reports on behalf of the ROTSE collaboration: ROTSE-IIIc, located at the H.E.S.S. site at Mt. Gamsberg, Namibia, responded to Swift GRB041223 (GCN #2898). A manual response was initiated at 18:27 UT, around 4.5 hours after the burst. We took 10 5-s exposures followed by 200 20-s exposures. The first images were taken during twilight, and all the images were taken with >90% moon illumination. The unfiltered images were calibrated relative to USNO A2.0. Individual images had limiting magnitudes around 16.8. Comparison to DSS (second epoch) reveals no new sources within the 3-sigma error circle to a limiting magnitude of 18.4 for a stack of the first 90 images.