TITLE: GCN CIRCULAR NUMBER: 30888 SUBJECT: GRB 210919A: iTelescope T-11 upper limits DATE: 21/09/27 09:23:47 GMT FROM: Takanori Sakamoto at AGU <tsakamoto@phys.aoyama.ac.jp> K. Hasuda, T. Sakamoto (AGU) We observed the field of GRB 210919A detected by Swift (Tohuvavohu et al., GCN Circ. 30846) with the iTelescope.Net (http://www.itelescope.net) T11 (Planewave 20" CDK) telescope located at the New Mexico Skies Observatory (NM, USA). 59 images of 60 sec exposures were taken in the R filter starting from September 21 on 10:04:47 (UT) about 2.4 days after the trigger and stopped on 11:26:12 (UT). We further obtained 60 images of 60 sec exposures in the R filter starting from September 22 on 10:01:34.4 (UT) and stopped on 11:27:50 (UT). We do not detect the optical afterglow both in the individual images and the stacked image at the XRT position (Goad et al., GCN Circ. 30850). The estimated five sigma upper limits of the combined image of the first observation (total exposure of 3540 sec) and the second observation (total exposure of 3600 sec) are 17.8 and 19.1 using the USNO-B1 catalog.