TITLE: GCN CIRCULAR NUMBER: 10426 SUBJECT: GRB 100213B: GRT Optical Observation DATE: 10/02/15 20:34:15 GMT FROM: Takanori Sakamoto at NASA/GSFC T. Sakamoto (UMBC/GSFC), D. Donato (ORAU/GSFC), N. Gehrels (GSFC), T. Okajima (JHU/GSFC), Y. Urata (NCU), C.A. Wallace (FGCU) We observed the field of GRB 100213B detected by Swift (trigger #412220; Vetere et al., GCN Circ. 10412) with the 14-inch Goddard Robotic Telescope (GRT) located at the Goddard Geophysical and Astronomical Observatory (http://cddisa.gsfc.nasa.gov/ggao/). Total 59 images of 60 sec exposures were taken in the R filter starting from February 13 23:55:15 (UT) about 0.94 hours after the trigger and stopped on February 14 01:50:46 (UT). We do not detect the optical afterglow both in the individual images and the combined image inside the XRT position (Evans, GCN #10423). The estimated three sigma upper limit of the combined image (total exposure of 3540 sec) is ~18.7 mag using the USNO-B1 catalog.