[vsnet-grb-info 20154] GRB 171211A iTelescope observation

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  22250
SUBJECT: GRB 171211A iTelescope observation
DATE:    17/12/13 03:50:35 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto at phys.aoyama.ac.jp>

Y. Kitaoka, T. Sakamoto (AGU)

We observed the field of GRB 171211A detected by Swift (Gropp et al., GCN Circ. 22234)
with the iTelescope.Net (http://www.itelescope.net) T27 (Planewave 27") telescope located
at the AstroCamp Observatory (Siding Spring Observatory, AU).  8 images of 60 sec exposures
were taken in the I filter starting from December 11 on 11:41:37 (UT) about 134 minutes after
the trigger and stopped on 11:54:45 (UT).  We do not detect the optical afterglow both in
the individual images and the stacked image at the X-ray afterglow position.  The estimated
five sigma upper limit of the combined image (total exposure of 480 sec) is ~17.2 using
the USNO-B1 catalog.