TITLE: GCN CIRCULAR NUMBER: 30213 SUBJECT: GRB 210610B: CrAO/ZTSH optical observations (correction to the GCN circ. 30212) DATE: 21/06/11 21:35:58 GMT FROM: Alexei Pozanenko at IKI, Moscow N. Pankov (IKI, HSE), A. Pozanenko (IKI), V. Rumyantsev (CrAO), S. Belkin (IKI, HSE) report on behalf of IKI GRB FuN: In the GCN circ. 30212 we we incorrectly reported GRB 210610A instead of GRB 210610B. The circular should be read as follows. We observed the GRB 210610B (Page et al., GCN 30170) with ZTSH 2.6m telescope of CrAO observatory starting on June 11 (UT) 19:46:53. The optical afterglow first reported by UVOT (Page et al., GCN 30170) is clearly detected in each of a single image of 120 exposure in R filter. Preliminary photometry of the afterglow in the first image is following Date UT start t-T0 Filter Exp. OT err (mid, days) (s) 2021-06-11 19:46:53 0.99683 R 1*120 19.50 0.12 The photometry is based on nearby USNO-B1.0 (R2) stars USNO-B1.0 id USNO_B10-1043-00282648 USNO_B10-1043-00282621