TITLE:   GCN CIRCULAR
NUMBER:  22516
SUBJECT: GRB 180316A: TSHAO optical observations
DATE:    18/03/18 18:33:32 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

A. Volnova (IKI), A. Kusakin (FAPHI), A. Pozanenko (IKI), I. Reva 
(FAPHI),  E. Mazaeva (IKI), M. Krugov (FAPHI) report on behalf of larger 
GRB follow-up collaboration:

We observed the field of GRB GRB 180316A (Melandri et al., GCN 22500) 
with Zeiss-1000 1-m telescope of Tien Shan Astronomical Observatory 
starting on Mar. 17 (UT) 23:19:40. We obtained several images in 
R-filter.  The optical afterglow (Lipunov et al., GCN 22502; Schady  et 
al. GCN  22504; Martone  et al. GCN  22507; Butler et al., GCN 22509; 
Breeveld et al. GCN  22510) is marginally detected in a stacked image. 
Preliminary photometry of the field is following.

Date        UT start t-T0     Filter Exp.    OT    Err.  UL
                      (mid, days)     (s)

2018-03-17  23:19:40 1.78280  R      36*60   21.5  0.5   21.0

The photometry is based on several nearby USNO-B1.0 stars.