TITLE:   GCN CIRCULAR
NUMBER:  7928
SUBJECT: GRB 080701A: Early RAPTOR optical limits
DATE:    08/07/02 23:24:50 GMT
FROM:    James Wren at LANL  <jwren@nis.lanl.gov>

J. Wren, W.T. Vestrand, P.R. Wozniak, H. Davis, B. Norman
of Los Alamos National Laboratory report:

The RAPTOR telescope system responded to Swift trigger
315615 (Stroh et al., GCN 7910) under good observing conditions.
Our narrow-field instruments began observing the location at
10:14:06.47 UTC, 28.8 s after the Swift trigger.  We detect no
counterpart at the improved XRT position (Evans et al., GCN 7914).
The limiting magnitudes of our unfiltered observations when
calibrated to the USNO-B1 R-band are given in the following table.
The GRB location was also within the field of view of our
continuous all-sky monitoring system.  We can place 3 sigma limits
at or below magnitude 9.4 during the time period within 2
minutes both before and after the trigger.  

t-mid(s)    exp(s)     mag     mag-err
--------------------------------------------
-11.68      10.0       9.7     3 sigma limit
11.57       10.0      10.0     3 sigma limit
34.80       10.0       9.9     3 sigma limit
71.45       45.0      19.3     3 sigma limit
173.93     100.0      19.8     3 sigma limit
300.65     100.0      19.9     3 sigma limit
561.10     270.0      20.5     3 sigma limit