TITLE:   GCN CIRCULAR
NUMBER:  16453
SUBJECT: GRB 140620A / iPTF14cva: TShAO optical observations
DATE:    14/06/24 23:39:18 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

A. Volnova (IKI), W. Mundrzyjewski (Fesenkov Astrophysical Institute),  A. 
Kusakin (Fesenkov Astrophysical Institute), A. Pozanenko (IKI) report on 
behalf of larger GRB follow-up collaboration:

We observed the optical candiadate iPTF14cva (Kasliwal et al., GCN 16425) of 
Fermi GRB 140620A  (Fermi trig. # 424934131)  (Fitzpatrick  et al., GCN 
16426)   with Zeiss-1000 (East) 1m telescope of Tien Shan Astronomical 
Observatory on June, 20 starting (UT)  21:22:56.  We took several images in 
R-filter. We clearly detected optical transient (Siegel et al., GCN 16432; 
Kelemen  GCN 16440) in a stacked image.

Details of the photometry are following:

date               UT start       t-T0           Filter   Exp.       OT
                       (mid, days)                               (s)

2014-06-20  21:22:56     0.68914    R        20*120  20.37 +/- 0.09

The photometry is based on  star USNO-B1.0 1397-0294956 (RA 18:47:28.76 Dec 
+49:43:44.5) assuming  R=16.35.