TITLE:   GCN CIRCULAR
NUMBER:  30614
SUBJECT: GRB 210610B: Assy optical observations
DATE:    21/08/08 05:33:17 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

V. Kim (FAI, Pulkovo Observatory), A. Pozanenko (IKI), M. Krugov (FAI), 
  N. Pankov (HSE, IKI),  S. Belkin (IKI) report on behalf of GRB IKI FuN:

We observed the field of  GRB 210610B (Lien et al., GCN 30600) with 
AZT-20 telescope of Assy-Turgen observatory starting on 2021-08-07 (UT) 
20:45:22.

We clearly detect the optical afterglow (Lien et al., GCN 30600; Hu et 
al., GCN 30602; Lipunov et al., GCN 30607).

Preliminary photometry of the optical afterglow in a stacked image is 
following

Date       UT start  t-T0       Exp.    Filter  OT    Err.  UL(3sigma)
                    (mid, days)  (s)

2021-08-07 20:45:22  0.47601    75*60   r'      21.28  0.05   23.6

The photometry is based on nearby PS1 stars.