[vsnet-grb-info 28075] GRB 210610B: CrAO/ZTSh optical afterglow photometry

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  30178
SUBJECT: GRB 210610B: CrAO/ZTSh optical afterglow photometry
DATE:    21/06/10 22:44:37 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen at iki.rssi.ru>

V. Rumyantsev (CrAO), A. Pozanenko (IKI),  S. Belkin (IKI), N. Pankov 
(HSE) report on behalf of GRB IKI FuN:

We report photometry of  GRB 210610B  afterglow (Page et al., GCN 
30170; Lipunov et al. GCNs 30173, 30176; Kumar et al. GCN 30174; 
Rumyantsev et al., GCN  30175; Hu et al., GCN 30177) obtained with ZTSh 
2.6m telescope of CrAO observatory.

Preliminary photometry of the optical afterglow in R- filter is following

Date       UT start    Filter Exp.   OT    Err.  UL(3sigma)
                               (s)

2021-06-10 20:19:24    R      1*10  16.11  0.02 21.5
2021-06-10 20:59:50    R      1*10  16.99  0.02 21.2

The photometry is based on the nearby USNO-A2.0 star
USNO-A2.0_id
1043-0282589 16:15:36.30 +14:23:18.2 R=16.88

We continue observations in BVRI filters and will report photometry 
after data receiving.