TITLE: GCN CIRCULAR NUMBER: 9735 SUBJECT: GRB 090727: GRT Optical Observation DATE: 09/07/29 19:19:45 GMT FROM: Takanori Sakamoto at NASA/GSFC T. Sakamoto (UMBC/GSFC), D. Donato (ORAU/GSFC), N. Gehrels (GSFC), T. Okajima (JHU/GSFC), T.N. Ukwatta (GWU/GSFC), Y. Urata (NCU), C.A. Wallace (FGCU) We observed the field of GRB 090727 detected by Swift (trigger #358520; Evans et al., GCN Circ. 9718) with the 14-inch Goddard Robotic Telescope (GRT) located at the Goddard Geophysical and Astronomical Observatory (http://cddisa.gsfc.nasa.gov/ggao/). 77 set of 30 sec exposures (excluding the bad quality images) were taken in the R filter starting from July 28 01:57:45 (UT) about 3.2 hours after the trigger and stopped on July 28 02:40:50 (UT). We do not detect the optical afterglow (Smith et al., GCN Circ. 9719; Gorosabel et al., GCN Circ. 9728; Moskvitin et al., GCN Circ. 9733) both in the individual images and the combined image. The estimated three sigma upper limit of the combined image (total exposure of 2310 sec) is ~16.6 mag using the USNO-B1 catalog.