TITLE:   GCN CIRCULAR
NUMBER:  19127
SUBJECT: GRB 160303A: ISON-NM early optical early limits
DATE:    16/03/03 12:10:37 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

L. Elenin (KIAM),  E. Mazaeva (IKI), A. Volnova (IKI), I. Molotov 
(KIAM), A. Pozanenko (IKI) report on behalf of larger GRB  follow-up 
collaboration:

We observed the field of the Swift   GRB 160303A (Beardmore et al., GCN 
19126) with 0.4-m telescope of ISON-NM observatory starting on Mar., 03 
(UT) 10:56:02, i.e. ~80 seconds after burst trigger. We obtained 30 
unfiltered images of 30 s exposure. We do not detect any source within 
XRT error circle (Beardmore et al., GCN 19126)  both in the first image 
and in a combined image:

UT start   t-T0         Exp.      Filter  UL (3sigma)
          (mid.,days)    (s)
10:56:02  0.00110        1*30    Clear   19.8
10:56:02  0.00971       30*30    Clear   21.7

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