TITLE:   GCN CIRCULAR
NUMBER:  23571
SUBJECT: GRB 181228A: KAIT Optical Upper Limit
DATE:    18/12/28 04:15:53 GMT
FROM:    Weikang Zheng at UC Berkeley  <weikang@berkeley.edu>

WeiKang Zheng and Alexei V. Filippenko (UC Berkeley) report on
behalf of the KAIT GRB team:

The 0.76-m Katzman Automatic Imaging Telescope (KAIT), located at
Lick Observatory, responded to Swift GRB 181228A (Moss et al.,
GCN 23570) starting at 03:03:30 UT, 613 s after the burst.
Observations were performed with an automatic sequence in the
clear (roughly R), V, and I filters, and the exposure time was 20 s
per image. We do not detect any optical afterglow candidate within
the XRT position error circle (Moss et al., GCN 23570),
neither in single image, nor in the co-add images.
The typical limiting magnitude of our single clear image is about
18.5 mag calibrated to the Pan-STARRS1 catalog.