TITLE: GCN CIRCULAR NUMBER: 12213 SUBJECT: INTEGRAL Weak trigger #6331: GRT Optical Observation DATE: 11/07/30 05:05:52 GMT FROM: Takanori Sakamoto at NASA/GSFC T. Sakamoto (UMBC/GSFC), D. Donato (UMD/GSFC), N. Gehrels (GSFC), T. Okajima (GSFC), Y. Urata (NCU) We observed the field of INTEGRAL Weak trigger #6331 with the 14-inch Goddard Robotic Telescope (GRT) located at the Goddard Geophysical and Astronomical Observatory (http://cddisa.gsfc.nasa.gov/ggao/). A total 204 good quality images of 5 sec (146 images), 30 sec (31 images) and 60 sec (27 images) exposures were taken in the R filter starting from July 27 04:05:04 (UT), about 102 seconds after the trigger (92 seconds after the notice), and stopped on July 27 06:57:47 (UT). We do not detect the optical afterglow both in the individual images and the stacked image inside the 3.63 arcmin error circle. The estimated five sigma upper limit of the combined image (total exposure of 3280 sec) is ~19.8 mag using the USNO-B1 catalog.