[vsnet-grb-info 19306] GRB 170317A: SAO RAS optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  21001
SUBJECT: GRB 170317A: SAO RAS optical observations
DATE:    17/04/07 20:23:42 GMT
FROM:    Moskvitin Alexander at SAO RAS  <mosk at sao.ru>

A. Moskvitin (SAO RAS),  E. Mazaeva (IKI), A. Pozanenko (IKI),
A. Volnova (IKI), on behalf of larger GRB follow-up collaboration:


We observed the field of GRB 170317A (LaPorte et al. GCN 20885)
with the SAO RAS telescope Zeiss-1000  + CCD photometer on March, 17
(18:12:00--19:58:03 UT). We obtained several images in Rc band.
The optical afterglow (LaPorte et al., GCN 20885;
Mazaeva et al., GCN 20886; Xin et al., GCN 20888;
Mao et al., GCN 20889; Kuroda et al., GCN 20899) is detected
in a stacked frame. Preliminary photometry is following

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

2017-03-17 18:12:00   0.38823     Rc     15*300  22.3   0.3  22.6

Photometry is based on nearby USNO-B1.0 stars
previously used in GCN 20886.