TITLE: GCN CIRCULAR NUMBER: 18725 SUBJECT: GRB 151212A iTelescope observation DATE: 15/12/27 04:48:03 GMT FROM: Takanori Sakamoto at AGU Y. Kitaoka, T. Sakamoto, A. Yoshida (AGU) We observed the field of GRB 151212A detected by MAXI (Nakahira et al., GCN Circ. 18685) with the iTelescope.Net (http://www.itelescope.net) T18 (Plane Wave CDK) telescope located at the AstroCamp Observatory (Nerpio, Spain). 20 images of 60 sec exposures were taken in the Red filter starting from December 12 22:43:00 (UT) about 8.7 hours after the trigger and stopped on December 12 23:17:03 (UT). We do not detect the optical afterglow both in the individual images and the stacked image at the X-ray afterglow position (Roegiers et al., GCN Circ. 18687). The estimated five sigma upper limit of the combined image (total exposure of 1200 sec) is ~17.0 using the USNO-B1 catalog.