TITLE:   GCN CIRCULAR
NUMBER:  41805
SUBJECT: EP250911a: SAO RAS optical observations
DATE:    25/09/11 23:47:13 GMT
FROM:    Alexander Moskvitin at SAO RAS <mosk@sao.ru>

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

We observed the field of EP250911a (Liang et al., GCN 41788, 
Evans et al., GCN 41802) with the 1-m SAO RAS telescope 
Zeiss-1000 equipped with CCD-photometer. We obtained 9 x 300 sec.
images in Rc band on September 11, 21:38:05--22:34:14 UT 
(t_mid - T0 = 13.12819 hours = 0.547008 days).

The OT (Quirola-Vasquez et al., GCN 41790, Angulo et al., GCN 41793;
Lai et al., GCN 41801) is clearly detected in the stacked image 
with the brightness of R = 21.90 +/- 0.11 (R_lim = 23.0 mag).

This preliminary photometry is based on nearby SDSS stars 
(magnitudes were converted with the Lupton 2005 equations) 
and not corrected for Galactic extinction.