GCN Circular 3534

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)