TITLE: GCN CIRCULAR NUMBER: 19133 SUBJECT: GRB 160303A: RAPTOR Observations During Gamma-Ray Emitting Interval DATE: 16/03/03 19:05:45 GMT FROM: James Wren at LANL J. Wren, W.T. Vestrand, P. Wozniak, and H. Davis of Los Alamos National Laboratory report: The RAPTOR network of robotic optical telescopes made observations of Swift trigger 677495 (Beardmore, et al., GCN 19126). The burst location was within the field of our wide-field monitor located in Maui, HI, which began a 10 s integration of the location beginning at 10:54:38.19 UT, 3.86 s before the Swift trigger time and during the gamma-ray emitting interval. We do not detect an optical counterpart to a limiting magnitude of 10.5. Our 3-sigma limiting magnitudes are based on a comparison of our unfiltered image to the Tycho-2 V-band catalog.