TITLE:   GCN CIRCULAR
NUMBER:  46228
SUBJECT: GRB 261110A: CrAO ZTSh optical observations
DATE:    26/11/11 17:26:22 GMT
FROM:    Alexander Moskvitin at SAO RAS <mosk@sao.ru>

A. Moskvitin (SAO), V. Rumyantsev (CrAO), A. Pozanenko (IKI),
A. Volnova (IKI), N. Pankov (IKI), O. Spiridonova (SAO) report
on behalf of IKI GRB-FuN and SAO GRB follow-up team.

We observed the field of the SVOM GRB 261110A (Wang et al., GCN 46215)
with the Shajn 2.6-meter telescope (ZTSh) of the Crimean Astrophysical
Observatory (CrAO) on November 10 and obtained two series in R band
(t_mid - T0 = 6.12 and 10.81 hours respectively).

The afterglow  (Wu et al., GCN 46218; Li et al., GCN 46219; Moskvitin
et al., GCN 46220; Angulo et al., GCN 46223) is clearly detected
in stacked images of the two epochs with the following parameters.

Date       UT start  t-T0     Exp,    Filter Obj      Err   UL
                     (mid, d) (n*s)                         (3sigma)
2026-11-10 17:51:58 0.25498    5*120  R      22.30 +/- 0.10  23.7
2026-11-10 21:43:16 0.45050   53*120  R     22.80 +/- 0.09  24.3

The photometry (Vega) is preliminary and based on nearby SDSS stars
(Lupton 2005 transformation) and not corrected for Galactic extinction.