TITLE:   GCN CIRCULAR
NUMBER:  30243
SUBJECT: GRB 210610B: AbAO optical observations
DATE:    21/06/16 21:40:26 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

N. Pankov (HSE, IKI), A. Pozanenko (IKI), R. Ya. Inasaridze (AbAO), S. 
Belkin (IKI), V. R. Ayvazian (AbAO),  G. V. Kapanadze (AbAO) report on 
behalf of IKI GRB FuN:

We observed the GRB 210610B (Page  et al., GCN 30170) with AS-32 
telescope of Abastumani observatory (AbAO) in R-filter on June, 13. The 
optical afterglow  first reported by UVOT (Page  et al., GCN 30170) is 
clearly detected is detected in stacked image. Preliminary photometry of 
the afterglow is following

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


2021-06-13 17:06:46   2.88564  R     72*60   21.25  0.14  22.6


The photometry is based on calibrations stars reported in (Pankov et 
al., GCN 30213).