TITLE:   GCN CIRCULAR
NUMBER:  40963
SUBJECT: EP250704a / GRB 250704B: SAO RAS optical observations
DATE:    25/07/05 01:03:17 GMT
FROM:    Alexander Moskvitin at SAO RAS <mosk@sao.ru>

A. Moskvitin, O. Spiridonova (SAO RAS),
report on behalf of a GRB follow-up collaboration.

We observed the field of the GRB 250704B (Wang et al., GCN 40940),
EP250704a (Li et al., GCN 40941) with SAO RAS 1-m telescope
Zeiss-1000 equipped with CCD-photometer. We obtained 6 x 300 sec.
exposures in Rc band on July 4, 22:55:08--23:38:07 UT 
(t_mid - T0 = 15.00 hours).

The OT (Schneider et al., GCN 40942; Malesani et al., GCN 40945; 
Brivio et al., GCN 40947; Perez-Garcia et al., GCN 40957; 
Gillanders et al., GCN 40958; Xin et al., GCN 40960; 
Mohan et al., GCN 40962) is clearly detected in our stacked image 
with the brightness of R = 20.80 +/- 0.18.

Preliminary photometry is based on the nearby USNO-B1.0 stars
and has not corrected for the Galactic extinction.