TITLE:   GCN CIRCULAR
NUMBER:  37987
SUBJECT: GRB 241030B: SAO RAS optical observations
DATE:    24/10/30 20:41:05 GMT
FROM:    Moskvitin Alexander at SAO RAS <mosk@sao.ru>

A. S. Moskvitin (SAO RAS), V. P. Goranskij (SAI MSU),
A. S. Vinokurov, V. S. Shergin (SAO RAS), A. S. Pozanenko (IKI),
N. Pankov (IKI, HSE) report on behalf of the GRB follow-up team.

We observed the field of GRB 241030B (Fermi GBM team, GCN 37980;
Klingler et al., GCN 37981; Evans, GCN 37983; Zhao et al., GCN 37984),
with the 1-m telescope of SAO RAS equipped with the CCD-photometer.
We obtained a series of 300 and 600 sec. Rc images started 15 min
after the trigger.

The OT (Fu et al., GCN 37985; Odeh et al., GCN 37986) is clearly
detected in our frames with the following brightness:
R = 19.59 +/- 0.06 (18:49:32--19:00:55 UT, t_mid - T0 = 20.89 min);
R = 20.61 +/- 0.07 (19:01:33--19:45:54 UT, t_mid - T0 = 49.39 min).
This preliminary photometry is based on nearby PS1 stars (magnitudes
converted with Lupton 2005 equations) and not corrected
for the Galaxy extinction. Further observations are ongoing.