TITLE:   GCN CIRCULAR
NUMBER:  6723
SUBJECT: GRB 070808: OPTIMA-Burst optical upper limit
DATE:    07/08/09 00:17:11 GMT
FROM:    Alexander Stefanescu at MPE  <astefan@mpe.mpg.de>

A. Stefanescu (1), S. Duscha (1), G. Kanbach (1), F. Schrey (1), A.
Slowikowska (2)(3), H. Steinle (1) ((1)=MPE Garching, (2)=FORTH,
Heraklion (3)=NCAC, Torun) of the OPTIMA-Burst Team report the following:

OPTIMA-Burst at the 1.3m Skinakas Observatory, of the University of
Crete, Greece observed the location of the XRT error-circle of GRB
070808 (GCN Circ 6718, J. R. Cummings et al.), starting at 2007-08-08
21:45:35 UT (3.3h after the burst).

We did not detect any source inside the XRT error-circle in 3 co-added
900s exposures in R-filter.

Our limit is as follows:

t-t_0 (mid-exp)       t_exp     R-limit
13229s (i.e. 3.7h)    2700s     22.0