TITLE:   GCN CIRCULAR
NUMBER:  30232
SUBJECT: GRB 210610A: CAHA 2.2m Second Epoch
DATE:    21/06/13 21:56:50 GMT
FROM:    Alexander Kann at IAA-CSIC  <kann@iaa.es>

D. A. Kann (HETH/IAA-CSIC), A. de Ugarte Postigo (HETH/IAA-CSIC, 
DARK/NBI), J. F. Agui Fernandez, C. C. Thoene, M. Blazek (all 
HETH/IAA-CSIC), A. Fernandez-Martin (CAHA), and M. Azzaro (IAA-CSIC)
report:

We re-observed the afterglow (Page et al., GCN #30160; Hosokawa et al., 
GCNs #30161, #30169; Xu et a., GCN #30162; Kumar et al., GCN #30163; 
Lipunov et al., GCN #30166; de Wet et al., GCN #30168; Sun et al., GCN 
#30185; Watson et al., GCN #30191; Zheng et al., GCN #30203; Kann et 
al., GCN #30211; Belkin et al., GCN #30214; Moskvitin et al., GCN 
#30229) of GRB 210610A, discovered by Swift (Page et al., GCN #30160) 
and also detected by Konus-Wind (Frederiks et al., GCN #30197) at 
redshift z = 3.54 (Zhu et al., GCN #30164; Dutta et al., GCN #30200). 
with CAFOS mounted on the 2.2m telescope at Calar Alto, Almeria, Spain. 
We obtained 6 x 600 s exposure in Sloan r'.

Stacking the images, the afterglow is well-detected, and we measure, 
against nearby comparison stars from the SDSS catalog (AB mags, not 
corrected for Galactic extinction):

r' = 22.57 +/- 0.04 mag at 1.27366 d.

This value is in good agreement with the observations of Belkin et al., 
GCN #30214; Moskvitin et al., GCN #30229, as well as the extrapolation 
of the decay found by Kann et al., GCN #30211.