TITLE:   GCN CIRCULAR
NUMBER:  9466
SUBJECT: GRB 090530: GRT Optical Observation
DATE:    09/06/01 01:50:08 GMT
FROM:    Takanori Sakamoto at NASA/GSFC  <takanori.sakamoto-1@nasa.gov>

T. Sakamoto (UMBC/GSFC), D. Donato (ORAU/GSFC), N. Gehrels (GSFC),  
T. Okajima (JHU/GSFC), T. N. Ukwatta (GWU/GSFC), Y. Urata (NCU),  
C. Wallace (FGCU) 
  
We observed the field of GRB 090530 detected by Swift (trigger #353567;  
Cannizzo et al., GCN #9438) with the 14-inch Goddard Robotic Telescope (GRT)  
located at the Goddard Geophysical and Astronomical Observatory  
(http://cddisa.gsfc.nasa.gov/ggao/).   
 
100 set of 30 sec exposures were taken in the R filter starting 
from May 30 03:33:00 (UT) about 15 min after the trigger and 
stopped on May 30 04:29:30 (UT).  We do not detect the optical 
afterglow (Cannizzo et al., GCN #9438, Flewelling et al., GCN #9439, 
Nissinen et al., GCN #9441, Malesani et al., GCN #9452, Im et al., 
GCN #9459) both in the individual images and the combined image.  
The estimated three sigma upper limit of the combined image (total 
exposure of 3000 sec) is ~18.1 mag using the USNO-B1 catalog.