TITLE:   GCN CIRCULAR
NUMBER:  34406
SUBJECT: GRB 230812B: SAO RAS optical observations
DATE:    23/08/13 22:20:02 GMT
FROM:    Moskvitin Alexander at SAO RAS <mosk@sao.ru>

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

We observed the field of GRB 230812B (Lesage et al., GCN 34387;
Scotton et al., GCN 34392; Page, GCN 34394; Zheng & Filippenko, GCN
34395; Lipunov et al., GCN 34396; Salgundi et al., GCN 34397; Ackley
et al., GCN 34398; Xiong et al., GCN 34401; Casentini et al., GCN
34002; Frederiks et al., GCN 34403; Mao et al., GCN 34404; Odeh et
al., GCN 34405) with the 1-m telescope of SAO RAS Zeiss-1000 equipped
with the CCD photometer. We obtained 3 x 300 sec. images in Rc band on
August 13, 20:14:15--20:31:46 UT under mediocre weather conditions.

The OT is clearly detected in our stacked frame with the brightness of
R = 20.45 +/- 0.07 (t_mid - t0 = 1.0589 days).

This preliminary photometry is based on the nearby SDSS stars;
magnitudes are converted using Lupton (2005) equations.