TITLE:   GCN CIRCULAR
NUMBER:  46133
SUBJECT: GRB 261029A: SAO RAS optical observations
DATE:    26/11/03 06:25:43 GMT
FROM:    Alexander Moskvitin at SAO RAS <mosk@sao.ru>

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

We observed the field of the GRB 261029A discovered by Fermi
(The Fermi GBM team, GCN 46071; Longo et al., GCN 46085; Scotton,
GCN 46098), SVOM (Goto et al., GCN 46072; Yu et al., GCN 46096;
Brunet et al., GCN 46117), AstroSat (Salunke et al., GCN 46089);
CGBM (Marrocchesi et al., GCN 46095); NuSTAR (Waratkar
and Grefenstette, GCN 46100); GECAM-B (Yu and Xiong, GCN 46108);
Glowbug gamma-ray telescope (Cheung et al., GCN 46112);
also followed by EP (Kan et al., GCN 46086).
The observations carried out with the 1-m telescope of SAO RAS
Zeiss-1000 on 2026-11-01T20:32:25--21:42:39 UT. We obtained
12 * 300 sec. images in Rc band under good weather conditions.

The OT (O'Neill et al., GCN 46073; He et al., GCN 46078; Wang et al.,
GCN 46079; Cotter et al., GCN 46081; Yin et al., GCN 46082; GCN 46084;
Sánchez Álvarez et al., GCN 46083; Shi et al., GCN 46088; Kang et al.,
GCN 46090; Ma et al., GCN 46092; Novotny et al., GCN 46097; Zhao et al.,
GCN 46099; Dimple et al., GCN 46101; Novotny et al., GCN 46102;
Rodríguez-Torres et al., GCN 46103; Hua et al., GCN 46104;
Yin et al., GCN 46109; also observed in NIR: De et al.,
GCN 46080; GCN 46093) is clearly detected in our stacked image
with the following brightness.

Date       UT start  t-T0     Exp,    Filter Obj      Err   UL
                     (mid, d) (n*s)                         (3sigma)
2026-11-01 20:32:25  3.81978  12*300  Rc     22.85 +/- 0.17 23.6

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