TITLE:   GCN CIRCULAR
NUMBER:  42065
SUBJECT: GRB 251002A: SAO RAS optical observations
DATE:    25/10/02 23:10:11 GMT
FROM:    Alexander Moskvitin at SAO RAS <mosk@sao.ru>

A. S. Moskvitin (SAO RAS), V. P. Goranskij (SAI MSU), V. V. Vlasyuk, 
V. S. Shergin, V. A. Egorov, M. A. Pritychenko, I. V. Afanasieva 
(SAO RAS), report on behalf of GRB follow-up collaboration.

We observed the field of the GRB 251002A (Saccardi et al., GCN 42060)
with the 1-m SAO RAS telescope Zeiss-1000 equipped with the new 
CCD-photometer. The observations started at 20:31:30 UT, ~17 minutes 
after the trigger. 

The optical transient (Palmerio et al., GCN 42061; Turpin et al., 
GCN 42062; Jelinek et al., GCN 42063; Juliá-Maroto et al., GCN 42064)
is clearly detected in the individual images with the brightness 
of R = 17.58 +/- 0.02 (t_mid - T0 = 0.41694 hours).

Preliminary photometry is based on the nearby SDSS objects 
(magnitudes converted with Lupton 2005 equations) 
and has not corrected for the Galactic extinction.

The observations with the 1-m telescope in BVRI filters 
and also with the 0.5-m telescope AS-500/2 are ongoing.

We are grateful to the SAO RAS staff for their technical support.