TITLE:   GCN CIRCULAR
NUMBER:  28226
SUBJECT: GRB 200803A: Chilescope optical upper limit
DATE:    20/08/07 22:07:23 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

S. Belkin (IKI), A. Pozanenko (IKI), M. Krugov (AFIF),  A. Volnova 
(IKI), E. Mazaeva (IKI) report on behalf of IKI-FuN follow-up collaboration:

We observed  the GRB 200803A (Fermi GBM Team, GCN 28196; Hamburg et al., 
GCN 28206)  with Chilescope RC-1000 starting on 2020-08-05 (UT) 03:53:45 
in r'-filter. We did not detect optical afterglow (Lipunov et al., GCN 
28202).

Preliminary photometry is following.


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

2020-08-05 03:53:45 2.03425     r'  6*600 n/d n/d  21.5

The photometry is based on nearby USNO-B1.0 stars
Ref.stars
USNO-B1.0_id R2
0270-0863045 16.4
0270-0862955 15.5
0271-0884796 15.0