TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3534 SUBJECT: GRB 050607: RAPTOR-S Early Optical Limits DATE: 05/06/08 00:11:19 GMT FROM: James Wren at LANL J. Wren, W. T. Vestrand, P. Wozniak, R. White, S. Evans report on behalf of the RAPTOR team at Los Alamos National Laboratory: The RAPTOR-S telescope responded robotically to GRB 050607 (Swift trigger 132247, GCN #3525). The first exposure began at 09:11:49.97 UT, 27.17 seconds after the trigger time and during the third peak in the 15-350 keV light curve of the GRB. Observations continued through morning twilight which began approximately 90 minutes later. Vibrations due to high winds degraded the quality of several of the response images. We do not detect the optical counterpart reported by Rhoads (GCN #3527). We are able to place the following limits on the early optical afterglow based on calibration to the USNO-A2.0 R-band (times are seconds since trigger): mag | mid-exposure | start | end | exposure limit | time | time | time | duration --------------------------------------------------------------------- 15.6 | 32.17 | 27.17 | 37.17 | 10 17.8 | 42.79 | 47.79 | 57.79 | 10 18.5 | 108.66 | 47.79 | 220.46 | 70 (sum of 7 10s images) 18.0 | 248.94 | 233.94 | 263.94 | 30 18.9 | 390.27 | 233.94 | 627.29 | 180 (sum of 6 30s images) 18.2 | 741.18 | 711.18 | 771.18 | 60 19.2 | 1303.89 | 711.18 | 1615.55 | 360 (sum of 6 60s images)