TITLE: GCN CIRCULAR NUMBER: 17402 SUBJECT: GRB 150203A: RAPTOR Limits Beginning at the Gamma-Ray Emitting Interval DATE: 15/02/04 15:53:14 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 629578 (Ukwatta, et al., GCN 17377). Our narrow-field instruments located in Los Alamos, NM, USA, arrived on target 4.6 s after receipt of the notice (T+30.9 s after the BAT trigger time). No optical counterpart is detected within the Swift XRT counterpart location. Typical 3-sigma limiting magnitudes for our initial 5 s exposures were R~16.6 and I~15.7 based on comparision to the USNO-B1 R-band catalog. The burst location was also within the field of view of our wide-field sky monitors during the gamma-ray emitting interval. No optical counterpart is detected in any of our wide-field monitor images. Typical 3-sigma unfiltered limiting magnitudes during this period were V~9.7 based on comparison to the Tycho-2 V-band catalog.