TITLE:   GCN CIRCULAR
NUMBER:  35839
SUBJECT: GRB 240225B: further SAO RAS optical observations
DATE:    24/02/29 18:48:28 GMT
FROM:    Moskvitin Alexander at SAO RAS <mosk@sao.ru>

A. S. Moskvitin, O. I. Spiridonova (SAO RAS)
report on behalf of the GRB follow-up team.

We observed the field of GRB 240225B (Nakajima et al., GCN 35796;
Evans, GCN 35797; Joshi et al., GCN 35798; D'Ai et al., GCN 35810;
Kawakubo et al., GCN 35811; Frederiks et al., GCN 35835)
with the SAO RAS 1m telescope Zeiss-1000 equipped with CCD-photometer.
We obtained 8 x 300 sec frames in the Rc band on Feb. 29,
17:11:52--18:03:46 UT (t_mid - T0 = 3.8903 days).


The OT (Gompertz et al., GCN 35805; Liu et al., GCN 35812;
Malesani et al., GCN 35819; Wise et al., GCN 35820;
Gompertz & Malesani, GCN 35824; Pankov et al., GCN 35826;
Ror et al., GCN 35830; Sasada et al., GCN 35831; Schneider et al.,
GCN 35832) is clearly detected in our stacked frame
with the brightness of R = 21.11 +/- 0.04.

The photometry is based on nearby SDSS stars (magnitudes converted
with Lupton 2005 equations).