TITLE:   GCN CIRCULAR
NUMBER:  38746
SUBJECT: GRB 241229B: Continued CrAO ZTSh observations
DATE:    24/12/31 23:03:47 GMT
FROM:    Alexei Pozanenko at IKI, Moscow <grb.alex@gmail.com>

N. Pankov (HSE, IKI),  A. Volnova (IKI),  A. Pozanenko (IKI), V. Rumyantsev
(CrAO),  report on behalf of the IKI-GRB-FuN collaboration:

We observed the field of GRB 241229B (Fermi GBM Team, GCN 38698; D'Ai et
al., GCN 38699) with 2.6-meter ZTSh telescope of CrAO. The observations
started on 2024-12-30 (UT) 18:30, i.e. ~1.73 days since GBM trigger. The
series of 30x120 s images were obtained using the CCD-photometer. The
optical counterpart (SVOM/VT team, GCN 38729; Volnova et. al, GCN 38732)
has been detected in a stacked image. Preliminary photometry is the
following:

Date        UTstart T-T0        Exp.   Filter OT   Err.  UL(3sigma)
          (mid, days) (s)

2024-12-30 18:13:33 1.73423     30x120 R      23.40 0.15 24.0

The photometry has been calibrated against nearby PS1 stars (see Volnova
et. al, GCN 38732).