TITLE:   GCN CIRCULAR
NUMBER:  19574
SUBJECT: GRB 160623A: TSHAO optical observations
DATE:    16/06/25 10:07:47 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

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

We observed GRB 160623A  (Vianello et al., GCN 19553; Mailyan et al., 
GCN 19555; Frederiks  et al., GCN 19554) with Zeiss-1000 (East) 1-m 
telescopes of Tien Shan Astronomical Observatory. We obtained several 
images in R filter starting on June 24 (UT) 19:19:17. We detect optical 
transient associated with GRB 160623A (Pozanenko et al., GCN 19561; 
Butler  et al., GCN 19567).   Preliminary photometry of combined image 
is following

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

2016-06-24 19:19:17   1.62157 R       40*90 20.57   0.10  22.0

Photometry is based on nearby USNO-B1.0 star

USNO-B.1_id     R2
1322-0479881    15.12
1322-0479687    15.57
1322-0479855    15.22
1322-0479927    17.43
1322-0479987    17.39